Hi all,
I have just purchased a network-connected video camera which runs Linux, and I would like to experiment with creating my own firmware for it. Since I am likely to brick the device a few times with this, I'd like to come up with a way of recovering it before I start.
The firmware (bootloader + kernel) is stored inside a 4MB SPI flash chip supported by flashrom, however it is soldered onto the board, so presumably to reflash it I will have to desolder at least one of the pins to avoid the flashrom commands getting tangled up with those sent by the device itself when reading the chip.
However I was thinking that instead of reflashing the entire chip every time something goes wrong, it would be a lot easier if I could produce my firmware image as a 4MB file, and emulate the chip so that the file is accessed directly every time the camera tries to read from the flash chip.
I see flashrom can already emulate some chips with the 'dummy' programmer, and as most (all?) programmers can both read and write data I am wondering whether it is possible to set flashrom up as a virtual flash chip connected to a real circuit, responding to read and write commands received from other chips in the device.
I plan to use a Bus Pirate as a programmer, so if I remove the flash chip and connect the Bus Pirate to the circuit instead, being able to edit a file and reset the device without actually reflashing anything would be a huge time saver.
If this isn't currently possible, would it be a big job to add support for it?
Thanks, Adam.