Firmware blob for ARM

Not sure how ARM's work but PIC -and AVR micro controllers store the source code internally and read protect it making it impossible to retrieve it.

I assume you want to retrieve the binary/instructions that are actually being executed on the ARM? Or have you actually retrieved the data and you simply want to decompile?

If you don't mind me asking from which device is it?
 
thanks for taking the time to reply.

i already have the data, a bin file (firmware upgrade from manufacturer) which i can successfully load to the cpu via the jtag interface i built

it is for a FTA satellite receiver, using an st20 (AKA sti5518 cpu)

the firmware does a cpu check..if cpu @60mhz do this, if cpu @80mhz do that.
the cpu can run at either speed.
mine is running at 60mhz which causes "undesirables" with the new firmware, so i want to either
1) disable firmware check
2) clock cpu to 80mhz, but i am having trouble understanding how the clock signal is determined from the datasheet.
 
Last edited:
Sry for the late reply, new year :p

Anyway I looked at the documentation for the CPU, what a document, by that I mean the shear size :D

Have you tried probing pins 122, 123 & 120 with a oscilloscope? They seem to control the clock signal.

I'm not much of a assembly programmer (I only did a little with PIC's & x86 but I don't much like it) and have very little experience with decompilation so seems to me it might be easier to try and increase the clock signal...
 
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