Updating GM EBCM Checksum
24 posts
• Page 3 of 3 • 1, 2, 3
Re: Updating GM EBCM Checksum
RADustin wrote:The problem is, one a bad file is uploaded- the module goes into a 'soft brick' mode and if another bad file is tried it will brick.
I have never ever seen that occur. Calibrations will never brick a module.
If you are writing over the operating system also, then thats a different story.
Your Local Aussie Reverse Engineer
Site:www.envyouscustoms.com
Mob:+61406 140 726

Site:www.envyouscustoms.com
Mob:+61406 140 726
Re: Updating GM EBCM Checksum
Tazzi wrote:RADustin wrote:The problem is, one a bad file is uploaded- the module goes into a 'soft brick' mode and if another bad file is tried it will brick.
I have never ever seen that occur. Calibrations will never brick a module.
If you are writing over the operating system also, then thats a different story.
My friend made me the hardware I’m flashing with... it basically emulates the MDI from what I understand and therefore flashes with the OS.
Currently I don’t have a way to cal only flash. Is your thought that if I could cal only flash, then it may work even with a bad checksum?
Re: Updating GM EBCM Checksum
RADustin wrote:Tazzi wrote:RADustin wrote:The problem is, one a bad file is uploaded- the module goes into a 'soft brick' mode and if another bad file is tried it will brick.
I have never ever seen that occur. Calibrations will never brick a module.
If you are writing over the operating system also, then thats a different story.
My friend made me the hardware I’m flashing with... it basically emulates the MDI from what I understand and therefore flashes with the OS.
Currently I don’t have a way to cal only flash. Is your thought that if I could cal only flash, then it may work even with a bad checksum?
It will never work with a bad checksum. But doing a calibration only flash is MUCH faster.
Update the programming to do calibration only, and also to keep retrying to flash when its incorrect.
When it detects its incorrect, you can automated the software to simply increase the checksum byte by 1 and reflash. Eventually you will find the value.
Your Local Aussie Reverse Engineer
Site:www.envyouscustoms.com
Mob:+61406 140 726

Site:www.envyouscustoms.com
Mob:+61406 140 726
Re: Updating GM EBCM Checksum
Tazzi wrote:
It will never work with a bad checksum. But doing a calibration only flash is MUCH faster.
Update the programming to do calibration only, and also to keep retrying to flash when its incorrect.
When it detects its incorrect, you can automated the software to simply increase the checksum byte by 1 and reflash. Eventually you will find the value.
I'll work on implementing this. It's going to take me some time just to see how to set it up, I'll have to quiz my friend on the bootloader.
any idea of a non brute-force way to figure it? Seems like assembly(IDA) had promise, but I don't know much about it. Is there anything I can do to make an assembly strategy more effective?
24 posts
• Page 3 of 3 • 1, 2, 3
Return to Engineering and Reverse Engineering
Who is online
Users browsing this forum: No registered users and 1 guest