Thread: Patched firmwares for JNX files

Without changing number and over 2.20 it went smoothly as well. Now Edge 800 is running 2.40 with jnx support.

Originally Posted by AlexWhiter

I see.

Could you please try to upgrade now to 2.40 without changing the version number in the patcher?

Originally Posted by 1ilya

Without changing number and over 2.20 it went smoothly as well. Now Edge 800 is running 2.40 with jnx support.

I'll check the version changing functionality.
Thanks for reporting this bug!

@AlexWhiter
Are you talking about changing firmware version or some other version?

@kunix
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.

Originally Posted by kunix

Did you think about patching the number that's used as RSA module? I think it's going to have very stable signatures

I'm not sure I understand what you are talking about

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.