Thread: Nüvi 3790

The coded link to the Wayback Machine on Internet Archive works fine for me, i guess it's due to your browser settings that it's not offering to save it automatically for you. Never mind, here's a Mega mirror to a zipped nuvi37xx_GCDFile__490.gcd: [Only registered and activated users can see links. ]

When you open the GCD file in RGN_Tool the HWID will be shown as 1101, you should not change that. After you apply the patch via Tools>nuvi 3790 patch, save it as 110101000490.RGN then use Updater.exe to flash it in preboot. This is what you need to do to patch and save:

Spoiler: Click for Image

[Only registered and activated users can see links. ]

If you're still unsure just ask again.

As for the risk of erasing nonvol, there's minimal risk it'll completely kill it. The only time i've experienced that has been when a device had badly damaged flash memory and exhibiting very weird behaviour due to totally improper previous flashings. Truth is maybe those few devices were going to die anyway and that final flashing just tipped them over the edge. There is always some risk in any flashing - just like a Medico will warn you there's some element of risk even when doing very simple surgery. Even flashing the patched fw carries a little risk tbh.

Ok i think i understand now what you asked for. So, this is what you did in sequence, right?:

• You tried updating it with GarminExpress after which the nuvi then would not fully boot, exhibiting a boot-loop when turned on.
• You then flashed Cure fw made from US/EU fw V5.10, recovered Mass Storage Mode then loaded original US/EU V5.10 (it's unclear to me whether you needed to remove any file/s, such as GUPDATE.GCD or a recently added *.IMG file, prior to loading original fw) after which it booted and worked but with functions missing and model as 3700.
• You flashed either (i) full SG/MY firmware (i now see you mentioned "34xx Sg" in post #3 which maybe was a typo because you said 37xx SG/MY above in #5) without altering it's HWID in RGN_Tool thus changing the device's HWID to 1288; OR, (ii) flashed hybrid fw made from US/EU (1101) boot.bin and remainder (fw_all.bin & resources.bin) from SG/MY with HWID override to 1101 thus retaining the nuvi's HWID as 1101.
• The device was then again in a boot-loop as a result of the attempt to convert it to SG/MY (as said, at this time it's unclear to me if it had HWID changed to 1288 with SG/MY boot.bin flashed or retained at 1101 with US/EU 1101 boot.bin and SG/MY remainder with overrides to 1101).
• You then loaded full US/EU 34xx fw successfully changing its HWID to 1376 but experienced problems with satellite accuracy and vehicle symbol jumping.
• All the above, regardless of HWID change or not or use of SG/MY 34xx or 37xx (because it doesn't much matter now), was done without backing up nonvol or clearing nonvol either before and after flashing due to you being unaware of those necessay precautions.
• You then converted it back to US/EU HWID 1101 and of course it's again got loss of functions and model as 37xx but you now understand the importance of both backing up and clearing nonvol. It's present state is US/EU 1101 and the only nonvol backup was done in that 'model-loss' 37xx state.

So now to your question as to why HWID is sometimes overridden and sometimes not. There's several scenarios but in your case it's briefly answered like this: The HWID is changed for safety if it's possible to do so. Using 'hybrid' fw, i.e. retaining both the original boot.bin and HWID, is safer than a full flash because if a re-conversion is required it's much more certain to be able to revert back to the original state that way. In the case of converting US/EU 37xx to US/EU 34xx the original boot.bin and HWID retention (hybrid) method doesn't work due to some region layout incompatibilities however a full conversion using unchanged/original/full 34xx does work because the region layout is changed accordingly, same with a re-conversion to 37xx too.

As far as the patching of 37xx fw to enable 3790 features in lower models is concerned, there is absolutely no reason to use HWID overrides and it would be problematic to do that anyway. Unless my understanding of what you've done is wrong, your device, regardless of all your flashing/cross-flashing, previous HWID changes and it now showing 37xx as model, has still got HWID 1101 - correct?

Flashing FULL SG/MY with HWID 1288 might work and let it boot fully. I think perhaps the boot-loop with both 1101 & 1288 HWIDs was because the US/EU bootloader in region 5 cannot work with SG/MY firmware in region 14. If you successfully flash full SG/MY it will change the device to 1288 also reset the region layout and load the SG/MY bootloader to region 5 so probably it'll boot up ok. However, my experience with many Asian firmwares on US/EU devices when used with Western voice files cause problems. Some full conversions to Asian can be permanent, as in 'one-way' with no possibility to re-covert to US/EU. Therefore i'd advise against it. There is also the possibility that you might hard-brick it doing a full conversion and have no chance to recover it at all using software methods.

It was always a long-shot that the RGN_Tool 3790 patch would work in this case. At least we've established that it doesn't fix the model loss problem.

You have only two options now: 1/ Leave it as is and put up with the loss of functions. 2/ Erase region 41 and hope that works.

If you want to erase it, make an SD kit using US/EU boot.bin renamed Ldr.bin and these commands in update.txt:
ergn,41
reboot
(ensure there's no extraneous spaces at line ends or unnecessary carriage return under 'reboot' if you copy and paste the above).

If you aren't confident to make it yourself post again requesting the kit. Reminder: I really don't think it'll harm anything but the risk is all yours if it goes wrong.

Hello Neil, thank you for all your help, after reading everything I have read I think I dare to make the kit for erasing from the card. Would the process remain like this?
- The nüvi now has version 490 with the RG-Tool patch for 3790.
- Copy of NV region 41. Version 490.
- Clear novol memory from the developer menu.
- Flash the nüvi to version 510, to leave it as it was when I applied Cure3 with cure and then original Cure3.
- Clear novol memory from the developer menu.
- Copy of NV region 41. Version 510
- Prepare the kit with the commands and copy it to an empty card. The kit would look like this:

Spoiler: Image

- Insert the card into the nüvi, turn it on and wait for the kit commands to be executed and the nüvi to reboot.
- Turn off nüvi and remove the card.
- Reboot and clear nonvol memory from the developer menu.
- Restart and see if there is any luck and we have recovered the nüvi 3790.

I have never told you something that I don't understand. Whenever I have performed a nonvol memory wipe from the developer menu, personal data has not been erased from the nüvi. It is normal?



Regards;

Yes that's the correct sequence and SD kit structure, well done.

You probably should clear nonvol before the initial copying of rgn41 too, although going by your final statement it doesn't seem to be really removing recent clearable data from it anyway (similar to where corrupt data in a folder/directory on a PC can't be accessed or removed). That further strengthens my belief that the nonvol region is poisoned so is indeed the likely culprit of the senior model function losses... so let's just hope that it can be erased properly so the device can re-write it cleanly on boot.

Seeing clearing recent data doesn't work i do wonder if the GarminDevice.xml in the onboard Garmin folder is also being updated properly on each boot-cycle but that's now of purely academic interest anyway. So press on and good luck mate!

Note: even if 41 erases successfully it might still show "nuvi 37xx" on the splash screen and also in the Inventory behind the battery symbol but hopefully with the 3790 features fully restored.

Hello Neil, I have done all the steps correctly but to no avail. The nüvi remains the same. User data has also not been deleted from the kit command, the kit ran fine but we have not been able to get the nüvi to have the functions. Now every time I turn the nüvi off and on it's like I did a nonvol wipe from the developer menu, when I start the nüvi I have to select a language. I do not know why.

Is it possible to perform an installation from scratch? Like when we format a PC with Windows and install everything again.

Thank you very much for your help.

Originally Posted by Choco

.......... User data has also not been deleted from the kit command

Well that's a most unwelcome result for sure. Previous model loss problems in 3790 have nearly always been resolved by erasing region 41 if the flash was successful. Certainly the fact that user data remains indicates nonvol was at best only partially erased.

Now every time I turn the nüvi off and on it's like I did a nonvol wipe from the developer menu, when I start the nüvi I have to select a language. I do not know why.

Try this: Select the Locale/Language then take it outside to get a satellite fix to see if it then goes to normal boot when re-started. It might take a while to get a good fix after a comprehensive re-set even if it was not fully executed.

Is it possible to perform an installation from scratch? Like when we format a PC with Windows and install everything again.

No, unfortunately that's not possible. The visible file system (contained in region 48) can be re-formatted of course but that won't help anything with this problem, it's not caused by what can been browsed and removed in Mass Storage Mode. The actual OS is a close-held propriety secret, it was loosely based on Linux but is far removed from that now and there's no install media available like with other operating systems. Anyway, let's check something else: If the flash completed, or even if it only started, in the 1101 folder there should be two new files created, last_id.bin and update.log. Please open update.log with any text editor like Notepad and post the contents but remove the IDs for privacy or just say what's below the dotted line. It's contents should something look like this:

nüvi blade Series Software Version 5.10, UID: 380xxxxxxx, HWID: 380xxxxxxx
------------------------------------------------------------------------------
Parsing "rrgn,41,1:/41.bin"
Success
Parsing "reboot"

If the 2 files aren't there it means that nothing actually flashed. If there is 'Error' instead of 'Success' in the LOG file then the flash started but failed.