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Topic: Bus Pirate V4 reconnects everytime I use flashrom (Read 150 times) previous topic - next topic

Bus Pirate V4 reconnects everytime I use flashrom


I have a Bus Pirate 4 and tried to use flashrom from Ubuntu 20.
Every time it starts the Bus Pirate reconnects the USB connection, resulting in a new USB address without
flashrom to do anything. I once had borrow a V3 four years ago and the process was flawless. Does anyone had the
same issue and could fix it?

This is the command I use:
flashrom -p buspirate_spi:dev=/dev/ttyACM0,spispeed=1M

The only hint I found through DMESG is:
USB disconnect, device number 5
failed to set dtr/rts
new full-speed USB device number 6 using uhci_hcd



Re: Bus Pirate V4 reconnects everytime I use flashrom

Reply #1
I think the issue is that there is a reset command issued before going into the binary mode for Bus Pirate. This is to make sure BP is initialized correctly and serial commands will not do anything weird down the line. In v3 this is not an issue as USB communication is handled by the FTDI chip. But in v4, USB is directly attached to the PIC microcontroller. If PIC resets, the whole USB stack restarts, resulting in communication loss.

I vaguely remember somebody posting patches where reset was just causing the BP stack to reset without touching any HW peripherals. Maybe community firmware has this implemented?