Thread: (Nuvi 660) Is it possible to convert OEM FW to regular one?

Originally Posted by snehne

* Loading gupdate.gcd into rgn_tool, It shows HWID 596, SW version 490, for both bin files (boot.bin and fw_all.bin). I could save either file, but gir_editor refused to load either because they are not logo or gir files. Actually gir_editor also refused to load the logo files from ddabcd277's links (error 6: overflow).

I don't know why turboccc GIR Editor don't want to open the logos I gave links. You should ask him. I have a feeling GIR Editor only support BMP RGB 565 and that is the reason. Better ask turbo. There could be also something wrong with this logos. I don't know.

Originally Posted by snehne

* I was able to add the logo.bin into the gcd file as the third bin file, and save it, but I am not sure what this will do. In particular, I could add another one (the 670 one), and when I load the modified gcd, I saw both of them listed despite they all have the same parameters. So I am wondering how the gcd works -- does it just load the sections in order, and overwrite earlier writes if later ones use the same address? In other words, if I just add it as the third bin file and load the modified firmware, would it be loaded over original and if it happens to be the region where the logo is accessed, then It gets replaced? From the addresses they don't actually seem to overlap ... but then since the firmware update does not change the splash, maybe the logo was at a different place. The addresses are:

boot.bin: section 0800, size 270048, RGN region 0C
fw_all.bin: Section BD02, size 10355456, RGB region 0E
logo.bin (from nuvi660OrigSplashScreen): Section 1005, size 270274, RGN region 10

You can flash the logo on section 1005 with only the boot from the firmware plus the logo after that you can save them to .rgn and flash. As I wrote use RGN Tool and if you have further questions better ask in the topic. Hope turboccc can answer.

Originally Posted by snehne

* I actually don't know if my splash screen is firmware preloaded -- all I know is that it does not get replaced by firmware update, and it shows up first thing (before the copyright info etc shows up). In the garmin/ directory of the gps, there is a file named gmapoem.img (51K). I am not sur eif this has anything to do with the splash screen? I suppose the img files are some kind of archive (because there is also the gmapprom.img, which is over 1GB, and I suppose it is the actual map); How do I unpack them (7zip or winimage won't recognize them)?

.img is the extention of garmin maps. Don't think it has some connection with the splash. Garmin maps can be opened with Mapsource. Can you upload your gmapoem.img?

I asked because there is a function to change the second splash screen from the menu of the nuvi. (not the factory firmware preloaded splash screen) It should be something like Tools -> Picture Viewer - > Image and the image can be set to be shown when unit powers on. Did you try this? Also do you have a folder Splash in the memory of your unit?

Originally Posted by snehne

* was able to get into maintenance mode by holding upper left corner while power up, but could not get into diagnosis mode (I think I once accidentally entered it, but now I could not recall how ...). I'll keep trying.

Hold the battery icon for 30sec and you should enter in the dignostic menu. After that search for Test..Start Test...after that tap More and make a shot. Better keep trying...search for simmilar screen: