Hello everyone,
I would like to ask if anyone has some experiences with dumping content of a flash while it is still located on the PCB.
I am just wondering because I did this for my last project and I ended up running into a bunch of problems. I am not 100% sure if the problems were related to that because it was my first time dealing with flashes but I found out in the end that there are a lot of issues related to that.
Is it always recommendable to desolder the target flash from the board or are there some other workarounds?
-Ramazuri
It's always recommended to desolder the flash chip. Otherwise there may be a few problems:
- You are essentially trying to power up the whole board via Bus Pirate. It's too much current draw.
- The pins are connected to other parts of the board. You cannot guarantee that those lines will be silent. For example the microcontroller may be using the same SPI data & clock pins for multiple SPI devices on board but can select one via CS pin.
- Even if the lines are silent, components on the board can degrade the signal. There may be pull-ups, pull-downs, resistor dividers etc.
I see, what I tried to do back then was to hold the CPU in reset which was possible due to the fact that there was a Reset pin right next to a GND pin. So I simply build a solder bridge between the two pins but I guess that is gambling. It might but also might not work.
I keep your advice in mind for the next time.