Middle Tennessee Geocachers Club (MTGC.org)
Web www.mtgc.org

Magellan GPS FAQ

By Robert Lipe, robertlipe at usa dot net. Part of my collection of articles

Revision History.

12/01/03 - initial version.
03/03/04 - Add links for external power, add firmware section, clarify USB speed, current drain, add rsrc links.
04/14/04 - Tweak firmware table. List version numbers of Mapsend, tighten those entries, list derivations.
05/17/04 - Add optimal unit orientation, DirectRoute route modification.
05/26/04 - Clarify region limits. Add DR "where did my streets go".
06/02/04 - SporTrak Color does have thermometer.
08/31/04 - Discuss DVD/CD compatibility, Windows XP SP2.
09/02/04 - Include link to SP2 fixes.
10/18/04 - Explain Topo 4.20D, firmware 5.3[56]
10/19/04 - Add fix for loss of weather screen
01/07/05 - Fix formatting in power consumption table, add brief mention of Topo 3D, DR 2.0., and 5.38. Clarify recommended firmware version.
01/11/05 - Clarify DR 2.0 even more based on feedback from support tech.
02/09/05 - Explain proximity and arrival alarms.
03/25/05 - Report success with large mem cards. Contrast Topo 3D vs. Topo. Tease for Explorist.
10/03/05 - Strengthen wording on hazards of > 64MB regions.
10/06/05 - Mention plat "north points south" compass bug.
10/06/05 - Cross-pollenate with Explorist.
11/01/05 - Add links for cables/parts, bluetooth.
11/11/05 - Add missing words for projection.
11/29/05 - Sketch in some "magic" key combinations.
12/09/05 - Attempt to clarify max region size.
12/15/05 - Explain international price variances.

Model comparison.

Magellan has a family of units that are more similar than they are different. 

Map 330, Map 330 Marine

This is the oldest of this family and is not really being actively marketed in most circles. The hardware differs from each other only in color. The key difference between these two models is the provided base map and the Points Of Interest being more optimized for land-lubbers vs. mariners.

SportTrak Map, SporTrak Map Pro

This is the lightest of the product families. The screen size is the same as the 330. These two units differ only in memory size, but they differ substantially in this regard.

SportTrak Color

Hi-res color screen. Built-in compass. New form factor. 

Meridian family.

These units all feature a larger screen than the others. The other key differentiator is that all models feature an SD memory socket for storage of detailed maps.

Explorist 210, 300, 400, 600, XL

These models were introduced in 2005. They're different enough than the rest of the models here to warrant a dedicated Explorist FAQ but since they share many traits with the rest of the units mentioned here, we try to mention them when we can.

In this table, when two units are listed inthe same line, it means they share the same electronics but differ only in bezel color, plastic color, and/or supplied basemaps.

Base Map (MB)
Detail Map (MB)
Screen Size
Screen Resolution
External Antenna Jack
Map 330/Map 330 Marine


SporTrak Map


SporTrak Map Pro


SporTrak  Topo
100 Topo


SporTrak Color
160x240 Color

Meridian Green/Yellow


Meridian Gold /Marine


Meridian Platinum

Meridian Color

120x160 Color

Why is the same GPS so much less expensive in the U.S. than in the UK or AUS or other countries?

The GPS is more than just hardware. The GPS includes a basemap. In the U.S. the basemap that's used is derived from the Tiger data collected by the Census Bureau and is therefore royalty free. Basemaps for other countries obviously come from different sources and there is a higher cost on them.

Can I then buy a unit in the US and install a basemap from someplace else?

Since you surely wouldn't be asking about liberating copyrighted data and would only use a basemap that you had already purchased on that very unit, sure. If you return a unit to Magellan, they can install (for a fee) a different basemap. If you return a unit to Magellan for repair that has a different basemap than was originally on the unit, they will reported reflash it back to the original or optionally charge you for that map "upgrade".

Using the Units

What is "Northfinder"?

Unless you are moving (or have a unit like the Platinum that has an integral compass) the GPS doesn't know which way "North" is. You can prove this easily by punching in a GOTO and rotating the unit in your palm. The arrow rotates as the unit rotates. With Northfinder, a picture of celestial bodies (sun and/or moon) will appear on the outer edge of the rose. Rotate the unit to align the picture of the sun with the actual location of the sun. Now "north" on your screen actually points north and the arrow on the "compass" screen points to your GOTO destination.

What is 'projection' and how do I use it?

Projection is computing one waypoint based on a distance and direction from another location.

To use it

  • From the position screen, choose 'projection'.
  • Select the starting point (from position, from user waypoint, city, etc.)
  • Enter your distance and bearing. If your distance is less than 500 feet, select .1 miles, leave the field, and then re-enter it. You can now edit feet.
  • You may now save the projected waypoint.

What are the limits of waypoints, tracks, and routes?

Waypoints may have eight characters in the name. (Explorist can have twenty.) The first 200 waypoints may have an additional 30 characters stored in 'comments'. (Explorist can have more.) Once those 200 slots have been filled, additional comments are siliently ignored. These limits apply even to the Meridians and Explorist where you can bank switch waypoints via the card utilities.

Tracks may have 2000 points.

Up to 20 routes may be loaded, each with a max of 30 points.   In version 5.x firmware, this limit has been raised to 50 points. 

How can I customize the bootup screens?

The Magellan 315 (and some competing units today) had a screen to allow you to personalize the boot screen to enter your name or contact information in order to help increase the odds of you getting it back if you lost it. Oddly, Magellan didn't bring that option forward into their mapping handhelds. There is a utility that will modify your firmware to change the "lawyer screen" to text of your choosing. http://www.navicache.com/freeware. This has to be done for every firmware update.

Another option, if you use Topo or Streets & Destinations, is to replace the "Woodall" screen. Edit

\ProgramFiles\Magellan\MapSend Topo\map\export.cfg
and replace the text in the [COPYRIGHT] section with your contact information. Up to eight lines are supported. Now the next time you upload a detail map, that text will change.

Explorist allows you to customize the boot screen from the keypad.

What is the best position to hold the unit?

The quad-helix antenna of these units works best when the GPS is held perpendicular to the ground. As a practical matter, you'll find that even when held parallel to the ground, you're likely to get adequate reception in most cases.

Even the 3-axis compasses in the units that have those claim to work when when unit is tilted, their optimial position is parallel to the ground, just like a magnetic compass.

Why does the unit take me past a waypoint then bring me back?

This is sometimes called "overshoot", or the "slingshot effect". The units perform some kind of motion averaging. If you briskly approach a waypoint (as geocachers often do) the units will generally take you up to a couple dozen feet past the point. As you stop, the unit will slowly (over a course of a minute or so) bring you back to the point in question.

Various people report it being different in different versions, lunar phasing, and so on, but it's been observed in all firmware versions as of this writing.

The slower you approach the point, the less pronounced this effect is. Some people will turn their unit off and back on to cancel the effect of this, but since that operation takes longer than just letting the unit settle, there are mixed votes for that. Beginning the search before the unit counts to minimal distance makes this a mere distraction. (Hint: don't walk past that hollow stump just because the GPS says your geocache is still 60 feet away...)

Explorist doesn't appear to share this trait.

Why does the weather screen report "no info"?

Though it's far from obvious, after a full reset, you must do a compass calibration before the barometer and thermometer work.

What is the arrival alarm in 5.x firmware? It's not in the manual

An arrival alarm will sound when you are crossing the selected distance threshold to the final waypoint in a route or the destination of a 'goto'. See also: proximity alarm.

What is the proximity alarm in 5.x firmware? It's not in the manual

A proximity alarm sounds when you are approaching the next point in the active route or the current goto. The 'distance' value has a fudge factor that seems to involve your velocity so that the alarm fires a few seconds from arrival. This is used to deliver the turn-by-turn pop ups for DirecRoute. See also: arrival alarm.

It's worth noting that Thales' use of the term "proximity alarm" for this feature is inconsistent with industry norms and bears little resemblance to what Garmin and others call proximity alarms.

What is the largest memory card I can use in a Meridian?

Firmware versions later than about Q2 of 2004 fixed the compatibility problems that had previously been observed with "large" cards. The yahoogroups report success with 2GB cards without issue.

What does 'audio prompting' mean?

What it doesn't mean is that the unit will speak to you. It does not. It will beep as you approach a turn if you're using DirectRoute. That's all. No spoken directions are given.

Map Types

There are two kinds of maps inside the receiver, base maps and detail maps.

Base maps come with the units and vary in size by model. Base maps are also used when the unit is zoomed out sufficiently. This can be disorienting - especialy on the models with 2MB basemaps - as a large number of roads will disappear when zoomed out. Base maps contain major roads, hydography features, and a few select streets in major cities. They also contain city names so they, too, are prone to "disappear" when zoomed out on the models with small base maps.

Basemap comparisons.  [ insert pictures of comparisons ]

Detail maps are created by you with one of the Mapsend products and uploaded by you to the unit. This is done over a serial connection for most models. On Meridian family, detail maps can be stored only on the removable SD memory cards which means you can use a USB card reader/writer to perform the upload much faster. Detail maps will contain the most features, including minor streets and POIs. Maps created by Mapsend Topo may contain contour data and POIs optimized for outdoorsmen.


Where can I get the latest firmware??

From Magellan

Should I upgrade to version 5 firmware?

Unless you have hardware affected by a fix (esp. specific 256MB Sandisk cards on Meridan) or you have DirectRoute, my personal advice is to remain on the lowest number above 4.06 that works with your hardware and mapping programs. Some folks on the list are happy with the newer versions, so it's up to you to decide.

4.00 the last version for 330.
4.06 A stable version, safe from many of the annoyances below
5.12 Required by DirectRoute/USA, fixes SD compat problems in Meridian.
5.36 Required by DirectRoute/Europe.

What has changed in 5.12 firmware since 4.06?

Magellan doesn't post an official list of changes (booooooo), but here is the observations of the Meridian Yahoo Group with a few of my own thrown in:

  • Compatibility problem with specific date codes of Sandisk memory cards solved.
  • 49 waypoints possible for each route (it was 30 before). You can't get to this from most software.
  • waypoints can be marked visible/unvisible.
  • there is a new parameter for showing the total distance to end of route.
  • proximity alarms (alarm when you near a waypoint). Note these have almost nothing in common with the Garmin feature of the same name
  • light turns on, when an alarm rings. Note this is a defectthat results inlower battery life and annoying keypress lossage to cancel light timer
  • goto line changed. During a route, the current "leg" will show like a railroad track
  • user maps will be shown first in the database/goto-list. resulting in extra keystrokes to navigate
  • goto-setting will not be lost, if unit is turned off. True only if a street route is active. Point-to-point routes are still lost.
  • browsing streets will now show the city in a different line, too.
  • tracks will be moved to routes in a different manner.
  • Rechargable Battery will be monitored better. I have personally seen no evidence that rechargeables are handled differently
  • scroll speed on maps was increased.
  • tracking fixed, when you tried to track with 0.01 km, it happened, that you got time skips, which resulted in date hops in mapsend.
What known defects are in 5.12?
fill in more later
  • backlight
  • flagrant disregard for user map settings
  • automatically clears goto once street route is done
  • frequent crashes observed by power users
What known defects are in 5.3[56]?
  • The major one is that it erases your track every time you do a street route. This is a deal-breaker for most US users of DirectRoute. DirectRoute Europe users have to live with this.
  • If you change the map or power cycle, it has to regain cold lock.
  • If you change the map from a DR map to anything else, it rejects the load with "Invalid Mapfile"
What about 5.38?

As of this writing, 5.38 hasn't made it to the web site, but at least one user got a unit back from repair and verified that the majority, if not all, of the problems present in 5.36 remain.

What long-standing defects are known?

  • The clock will fall out of sync with reality. The only known recourse is a "reset all" which, of course, clobbers all user data. This has been observed on all modern mapping Magellan models.
  • Sometimes the units seem to mark all birds in the sky as unusable. In extreme cases, this will result in loss of lock of position. A "reset all" cures it. This has been observed on all modern mapping Magellan models.
  • On the Plat, the compass sometimes points exactly 180° the wrong way. This means instead of pointing north, the compass points south. This can be cured by a "clear all memory" operation followed by a compass recalibration. A less drastic solution that often works is to toggle the compass from magnetic to gps orientation, then back to magnetic.

Available Strains

Mapsend Steets 1.0 - street level maps, very few POIs, can't print.
Mapsend Steets & Destinations - street level maps, adds POIs for zoos, ATMs,
Mapsend Topo 4.20D - adds topographical contour lines and POIs for arches, springs, and such.
Mapsend Directroute 1.0 - New in 11/2003. Delivers turn by turn driving directions, additional POIs.
Mapsend Topo 3D - New in 12/2004. Combines a higher resolution topo data and POI than 4.20 with maps improved over DirectRoute.

The first three mutants use the same street data and are derived from the Tiger maps. DirectRoute and Topo 3D use data licensed from Navtech.

Can I make a region that isn't rectangular?

No. Mapsend can only create rectangular regions. Yes, this is a bit of a drag when you're trying to map, say, a long interstate trip that runs NW->SE.

Can I upload more than 4 regions at a time?

No. But the 'card utilities' option on the Meridians makes it possible to change between multiple map images, each of which can contain up to 4 regions(except for DirectRoute and Topo3D, which can only do one at a time).

How big can a region be?

The answer differs between Mapsend products.

The older products (like "Streets" and "Topo/USA") allow you create single map sets consisting of 4 rectangular regions, each of which can be up to 16MB.

DirectRoute 1.0 and 2.0 allows you to create a single rectangular region of up to 64MB.

DirectRoute 3.0 allows you to create a single rectangular region up to 122MB.

TopoUSA/3D allows you to create a single rectangular region of up to 241MB.

Can I increase the region size?

Some users report satisfaction increasing the limit in mapsend.ini to allow larger regions. Many users report lockups, poor map performance on scrolling or route computation, map corruption (wrong street names) and other mysterious behaviour after using this unsupported modification. Since the firmware doesn't well support 'search by address by nearest' you will find that as your region sizes go up, the joy of searching for street names goes down because of both speed and volume. It takes the GPS longer to display all the "main streets" in two timezones than it does in one. Since the unit does not sort POIs by proximitiy or along your route, if you search for "123 main street" or "fast food->McDonalds", be prepared to get an unusably long list of choices.

A recommended approach is to create separate maps for different sections of the country, keeping the sizes down. Mapping 1 or 2 states per region and flipping between them with Card Utilities seems the best compromise.

Note that DirectRoute won't route between regions, so try to pick your regions to cover a days worth of driving, perhaps with a little overlap.

I have a Meridian. How can I put maps directly on the SD card?

Using Streets & Destinations or Topo 4.20, choose the 'upload region' option and select "to flash card writer". Note that this option (stupidly) doesn't
allow you to rename the file, so you'll have to rename it using File Explorer or another tool after it's done uploading. (If you have Topo 3.0, contact Magellan support for an update.)

What's the deal with Topo 4.20D vs. Topo 3.00?

Topo 3.00, which shipped until around the summer of 2003, didn't support direct writing of maps to SD cards used in Meridian, introduced in late 2001. Topo 4.20D adds the ability to write to SD cards (albeit with a single filename, so if you want more than one file on your SD card, you have to reach behind its back and rename it...) and a track editor.

There is no difference in the maps.

Magellan never really announced the upgrade and for the longest time was reported to have denied that it existed. The upgrade isn't downloadable but must be ordered directly from Magellan. Oddly, people report costs for the upgrade varying from zero to $25 USD and some people have to return their original media and some do not.

The difference between Topo 3.00 and 4.20D sounds pretty small. Why can't I download that and why should I to pay for an 'upgrade' to add support for my hardware that existed long before I bought 3.00??

Those are lovely questions to ask Magellan when you place your order.

What is Topo 4.20C?

It was never officially released by Magellan but has been seen floating around the net.

Can I use Mapsend to write tracks, routes, or waypoints directly to the SD card?

No, but GPSBabel can fluently convert between SD card format and Mapsend files.

Can I upload maps from my favorite program to my receiver?

No. (Well, unless your favorite program happens to be Mapsend.)

Can I scan my own maps?


Can I edit the maps?


Can Mapsend autoroute?

Only DirectRoute can.  With it, you can enter a start address and an end address (or waypoint or other destination) and let Mapsend pick the best way to get there from here.

Can I modify the route DirectRoute generated?

Not really. You can accomplish this somewhat by breaking the route into smaller pieces, setting endpoints at the key vias. You do have to manually chain the gotos when doing this; if you route from A to C via b, when you arrive at B, you have to enter a new GOTO for C. Alternately, just go where you know you want to go and press GOTO twice to make it perform a route recalculation. As you approach B, the odds of it rerouting through B increase.

I use DirectRoute. Why does it sometimes not show the street name of an approaching turn?

The street names of turns you're approaching are in actuality comments on hidden waypoints with names like 'M001'. The modern mapping Magellans have a limit of 200 waypoint comments. So if it has 195 waypoints with comments (easy enough to do if you're using software to load them) and you generates a route, only the first five street names for approached turns will be available. Of course, if the unit was already "full" when you generated the route, you will get no street names.
The only way to get street names to work is to clear some waypoint comment space by deleting comments and/or waypoints with comments.

I installed DirectRoute 1.0 and it keeps asking me to insert the original CD which is already in the drive?

You need the Update from Magellan.

Now that I installed Windows XP Service Pack 2 why does DirectRoute 1.0 keep asking me to insert the original CD in the drive.?

You need the Update from Magellan.

Someone mentioned DirectRoute 2.0. What's that?

It started shipping sometime around 12/2004. Magellan doesn't formally release lists of differences in versions any more, but one support tech confirmed that it's nothing more than DirectRoute 1.0 with the above fix for Service Pack 2 rolled in.

How good are the maps?

The accuracy of the maps varies by region. In some areas, offsets of several hundred feet have been reported while in others, new subdivisions appear on the maps in the right place. In general, the accuracy of DirectRoute and Topo 3D is much greater than that of the products using the Tiger maps.

How large of a map can I fit in my unit?

As a tangible example, I have included screen captures of the largest region from Mapsend Topo 4.20d that would fit into a SporTrak Map, a Map330, and estimated the size of a region that will fit on a 128MB region for a Meridian.  (Note that a single region of this size is an exceedingly bad idea and cannot be created by Mapsend without unsupported modifications to mapsend.ini. It's only here to give you an idea how much geography can be covered in that size of a flash part.)   The Maps are clickable for additional size.

Comparison of Map330 & ST Map

These maps are chosen to fill the memories on a Map330 and a SporTrak Map. They cover the area around Nashville, TN, north of the KY state line and south of the AL line past Huntsville.   The difference was chosen in the width of the maps.   The 330's additional memory will get Chattanooga and the Land Between the Lakes.

120MB vs. Map330 vs. ST Map

This map shows how spacious an SD card can be.  As you can see, this covers from north of Chicago, south of Jacksonville and Baton Rouge.

Height, Miles
Width, Miles
SporTrak Map
Map 330
Meridian 128MB
860 470

Should I buy Topo3D or Topo?

Topo3D has higher resolution topo data (30m instead of 90m) and replaces the 90's vintage Tiger street maps with the Navteq street and POI data similar (though not identical to) that provided with DirectRoute. The older (Tiger-based) versions, oddly enough, contain more detailed road and trail data for things like roads inside state parks. Use the Magellan map preview page to contrast them.

Hardware Problems.

330 Power cables. A batch of bad data/power cables shipped for the 330 in 2001. If your unit seems to deplete batteries while in the car, contact Magellan for replacement.

SporTrak Case Cracks. The screws used to hold the two halves of the shell can result in bulging and/or cracked plastic on that half. Contact Magellan for repair.

Meridian screen blobs. When the backlight is used, some models have bluish "blobs" that are apparent. The blobs don't move, but they can grow over time. Contact Magellan for repair.

I see a gap around the battery door on my Meridian. Won't that leak?

It's normal to be able to see light through that. The key is the rubber gasket that sits around the flange surrounding the battery compartment. Be sure to keep it clean in order to keep the integrity of the seal.


Are the serial/power cables for all units mechanically identical?

Almost. The head on the cables for the SporTrak and Meridian families are identical. The housing of the 330 (and 315 and predecessors not covered by this FAQ) has a flat back while the newer models have a curve to them. The pinouts are the same and it's possible, if you're patient enough, to use the cable from one family on the other if you bend the "fingers" on the cable out to increase their reach a little.

Are the serial/power cables for all units electrically identical?

Almost. The earliest cables, originallly for the 310/330 family, provide less power than the current cables. They will intermittently fail to power a Meridian operating at maximum power consumption. This is most typically seen as the Meridians powering off or draining batteries when operating with the backlight turned on the brightest. It's rumoured the oldest ones have black boxes for the regulators inline of the cable, but there isn't a direct correspondence between color of the plastic housing and the regulator inside it.

Can I make my own cable?

If you place any value on your time, I wouldn't suggest it. This page shows how it's done for the "flatback" models. It should probably work for the curve back models if you have enough clearance on the springs or tacks.
If you don't want to make your own connectors, sources include Gomadic and PC-Mobile.
Can I make a data cable into a data/power cable?

Some of the older cables brought the wire through. If you added a cigarette lighter and an inline voltage regulator to bring the power to about 3..5volts, it could be done. (If you don't know what an inline voltage regulator is, this project is NOT FOR YOU. Connecting 12v directly to the unit will reduce your Magellan to a pile of molten slag.) Apparently the newer cables that are now leaving the factory no longer have this wire.

Why doesn't Magellan get with it and ship units directly with USB?

A large market for these receivers is in navigational systems that conform to the NMEA 0183 standard and that spec uses multidrop serial, not USB. While there isn't a USB connector on any current Magellan, the pain of large transfers can be offset by placing an SD card on a USB card reader.

The new (early Q2, 2005) Explorist 300, 400, and 500 units have integral USB.

I have no available serial ports on my PC - what can I do?

Use a USB/serial converter. It's more than a cable; there are active electronics involved.

Will a USB adapter speed my serial transfers?

Very doubtfully. The total link speed is still bound by the slowest link in the chain. That link is almost certainly the physical interface on your Magellan and not the serial port on your computer. Even if you have a super-spiffy USB 2.0 serial adapter that's talking at 480Mbits/second to the host, the speed is still limited by the max speed of the serial interface (a max of 115.2Kbits/sec) when talking to your unit.
Attaching a firehose to the straw of your big gulp won't help you drink it any faster.

Can I make my serial Magellan GPS Bluetooth? You can attach a bluetooth unit that will speak serial to your unit and Bluetooth to your computer or PDA. One such product is available from PC-Mobile

Batteries & Power

What is a typical battery run time?

That depends on a number of variables. Depending on the model, the stated answer starts around 12 hours on a set of alkalines with deductions for use of backlight and the compass on the units equipped with one. The general consensus of the population seems to be that these times are optimistic. If your unit runs considerablly less than that on new batteries (1-2 hours) contact Magellan for repairs.  

Can I use rechargeable batteries?

Yes. For anyone shopping for battery technologies, NIMH is the chemistry in vogue right now. The Magellans don't have a battery type option, so be aware that a fully charged NIMH battery will produce less voltage than a new alkaline. This means the battery life indicatior will never show 100% on rechargeables and that the amount of time from "low battery" alarm to shutdown is short. I use 1800mAh batteries in my units and average about 9 hours from them without backlight.

Can I use lithium batteries?

Yes. These batteries are expensive, but work well in polar climates and have observed runtimes of over 20 hours.

Can I recharge batteries while they're in the unit?

No. This adds cost, weight, and liability issues to the product. You must place batteries in an external charger.

What is a typical current drain?

In Feb 2004, "coolerman" from the Meridan yahoogroup reported the following measurements from a Fluke 87 DMM:

With new Duracell 1500 mAh batteries I measured the following
Unit Off:  pulls .14mA or 140 uA This explains why the batteries go dead even if the unit is never on.
Unit On: Current  peaks at 290 then settles down to a pulsing 140 to 190 mA once per second while locking on to Sats.
	It was later confirmed this could be stabilized by 
	disabling the NMEA output via the setup screen
Unit Locked on Sats: Current pulses 140 to 190 mA once per second.
With backlight on low it pulses 230 to 290 mA once per second
With backlight on high it pulses 320 to 370 mA once per second
Then I took a battery pack with 2 brand new 1.5V Duracell batteries and attached them to the external connectors.
Unit on Locked on: Current from external pack is 133- 155 mA
With Backlight Low: 168-180
With backlight High: 178-194
It appears that the unit will draw a small amount of power from the 
internal batteries even while connected to outside power.
How can I power my unit from wall power? The easiest way is to use the auto power cable and one of the "wall warts" that provide a cigarette lighter jack. These are commonly available for cell phone chargers and such. In no particular order, and not as an endorsement, you can see examples at:

Radio Shack 22-505

Another option if you're interested in powering from the PC is the plates that plug into your floppy drive power cable and bring power out through a a drive bay. Again, in no order and not as an endorsement:

Undocumented Menus

What undocumented menus are there?

There are "hidden" keypresses and menu options on most units. The available options vary somewhat between models and firmware versions.NOTE:Some of these combinations can do Bad Things to your receiver and render it inoperable. Do not mess with these things unless you know what you're doing.

Function Sportrak Color Sportrak Map/Pro Explorist
Emergency power OFF ZoomIn+Enter+Goto ZoomOut+ZoomIn+Goto NAV + MENU + PWR
Upload Firmware ZoomOut+Left+Power Nav+Menu+Power LIGHT + ENTER + PWR

Additional Resources

Robert Lipe's other tech articles
Robert Lipe's DirectRoute Review
FAQ for Explorist
Magellan Meridian Yahoo Groups (good stuff - by far the most active)
Magellan 330 Yahoo Groups
Magellan SportTrak Map Yahoo Groups