trying to recover bricked pcm

so while flashing my 2008 subaru sti my usb cable gliched like just bent "the wrong way" and disconnected 20% into the flash thus timed out now i can no longer communicate. im trying to build usb to serial device so i can boot flash the board and hopefully recover it. does anyone have experience with this?

There’s a good writeup on how to do it on another forum. I built my circuit a couple weeks ago as I bricked an ECU and got it recovered from a friend of mine and I wanted to do it myself if it happens again.

It can be done and if you know how to build circuits it’s not very difficult. The only thing is that you need to integrate a 555 timer circuit for the watchdog.