Thread: GPSMAP 78s

It should have tried to re-boot at around the same time Updater finished. Force it off and see if there's anything new created on the card, Update.log and 41.bin as i said in previous post.

Ok then, it's some progress but maybe not enough. Since the modded V7.30 ramloader flashed properly at least G7ToWin is reporting correctly.

But it's what is in the update.log i need, if that file is present. The content of the update.txt file is what you've given me.

If there's no LOG file created this isn't really working.

The name would be "gmapsupp.img". It's not a raw image like used for a copy of a CD/DVD media; it's a Garmin proprietary format file used for mapping data reading by the device. The "supp" part of the name is used by Garmin for a secondary i.e. supplementary, map/chart on a device, gmapprom.img is mostly used for an internal primary map.

I understand that you're meaning Mass Storage Mode was available only for a brief time for you to see its internal files, GE only connects in MSM and not pre-boot mode however WU can handle both modes.

If you can get it stable in MSM for long enough again, move that most recent IMG file off the device but don't delete it straight away, copy it over to your computer somewhere first then delete it off. Make sure you have "Hide known file extensions" unchecked for your computer. Go to File Explorer Options>View to ensure and while there, in case we need the setting for later, also ensure some others, including system files, are like this:

Spoiler: Image

[Only registered and activated users can see links. ]

Open gmapsupp.img in [Only registered and activated users can see links. ] then press Info or Details button on GUI to see if it reports any errors there. If it shows as good, then it's not causing this havoc on the device.

Seeing all the other on-board files are much older, the gmapsupp is the only one that's likely to be incomplete or corrupt. If it's bad the device might boot up completely without it on-board while complaining about "no detail maps found ..." so try to boot it without the IMG file anyway regardless of what GMapTool reports. As a last resort if you can keep it stable in MSM,you can reformat the internal memory in FAT32 using [Only registered and activated users can see links. ] but only after copying the entire internal memory contents - do not use the built-in Windows formatting tool for formatting, Garmin devices are fussy on the format and keep that as an absolute last resort.

This inconsistent and flaky behaviour is much more symptomatic of a failing flash chip than a bad on-board file so we're really clutching at straws now but with absolutely nothing to lose.

so, i have gone over this again and again trying to find some detail you as a techie would need, i can only offer a couple things:
1) email sent to garmin support when this started 19-nov-2024:

Trying to install maps form MAp Installer Topo software and now unit is corrupt - it wont stay connected via USB anymore and after trying many cable/PC combinations no luck. It needs to have batteries removed after powering down before powering up. Master rest also doesnt work

How can I force a firmware update not using Express/Updater - neither of those programs work since USB connectivity wont stay up long enough to allow software to update firmware.

2) i have tried copying the files off more than 1x - never could get the unit t connect to laptop long enough and stable enough to get a copy - my 1st thought when this started happening was the nuclear option of a format and rebuild it...

3) between trying to fix this winter of 2025 and now - i had batteries pulled out of it... in winter 2025 i decided i was down to option of shipping away at cost of $$$ to ry and recover it, so prepped for mail on my desk with no batteries... when i figured i would make 1 last attempt it was after a number of months with no batteries after it started acting odd...

i going to have another go at this, but i did notice that the gmapsupp file large when compared to my other devices - as on the 100mb to GB range...

do you have any idea why this happened - or jut a bad chip or 1 of those things that happen?

My instinct has been and continues to be that it's most likely a failing chip.

This is where it's at:

• MSM is unreliable, transitory at best
• It's not seeing an SD card in a normal and reliable way to load anything from it using TXT commands
• Pre-boot is available and is in fact its current default mode
• Flashing with a modded ramloader RGN has somewhat restored it

The undisputable facts are that a stalled boot with "System Software Missing" message can be caused by one of only two basic problems - (i) a bad chip; or (ii) corruption of data in an essential region. Usually that corruption's in rgn14 (fw) or, if it's severely corrupt, perhaps in rgn41 (nonvol). The other cause as said is a physically failing chip but very often when that happens pre-boot isn't available at all. So, the only reason i was prepared to go down this rabbit-hole at all is because you have pre-boot, thus leaving some feint hope of a complicated "soft" failure.

Region 14 is certainly corrupt in your 78. When the unit boots, the "fw_all" data in 14 is involved and the device cannot get very far into a boot-cycle without that data fully working, definitely not far enough to recognise any inserted card. The modded ramloader i supplied bypasses that involvement to allow a card to be seen and for SD commands to be executed, however hasn't yet worked for you. You should try that again, but this time add an empty "update.log" file to see if that helps. I've seen a few devices over the years that wouldn't flash from a card without that file in place. It is worth a try anyway. Extract this ZIP and add the LOG file: [Only registered and activated users can see links. ]. The only files in 1113 folder should be the original update.txt and the added empty update.log. Then try to dump rgn41 again using Updater.exe and the modded bootloader RGN file.