You can read from the link given in post one:
This format is supported by the following Garmin devices: Astro 320, Colorado 300/400, Dakota 10/20, Edge 800, Etrex 20/30, GPSMAP 62/78, Montana 600/650, Oregon 200/300/400/450/550, Rino 610/650/655.Code:Please Login or Register to see the links
Firmware versions supported by the patcher
Colorado 300/400 3.50, 3.60, 3.70
Code:Please Login or Register to see the links
Are you talking about changing firmware version or some other version?
I was talking about changing the FW version.
Starting from version 2.9, the patcher can adjust the firmware version by the specified value (the same feature as in RGN Tools).
But it seems that there's something wrong with this adjustment.
I've checked the patcher, however, I could not find anything abnormal both in the code, and in the results it produces.
How do you find the FW version?
As for me, at first I determine FW's base address (exact method depends on firmware type, most frequently I substract offset of 5A A5 from 2nd dword of FW), and then I use the fact that 3rd and 4th dwords point to HWID and SWVER respectively.
In fw_all.bin, my code does the same as you've described.
But to change the FW version does not only mean to change it in fw_all.bin, but also in all other subfiles in GCD container.
So it's necessary to enumerate them all and to change their headers in GCD.
ok, I understand now.
Did you think about patching the number that's used as RSA module? I think it's going to have very stable signatures
Last edited by kunix; 24th October 2011 at 21:39.
I've read at your site that JNX files are locked with asymmetric encryption. I suppose that RSA is used because Garmin have already used RSA in GMA protection. If you replace RSA module number (which is the biggest part of public key), you can create RSA signatures by your own.