Flashed bad/wrong file to CTC dual motherboard 8u2 chip

[Edmund]

I have a CTC dual (makerbot clone). I got this from someone for pretty cheap. I have a flashforge creator pro clone that I've flashed sailfish to before so I thought it'd be the same thing. Seems like the bootloader was locked on this board. I ordered a usbasp and proceeded to "unlock" it. Not sure exactly what I did, but I flashed a bad or wrong .hex file to the 8u2 chip and now I no longer have usb use. Does anyone have any idea how to fix this or willing to read their hex file and send it to me? I was still able to upload sailfish 7.7 but would still need usb use.

[Rich Webb]

You don't normally need to fiddle with the 8u2 since it's just a pass-thru to the main uC. If you want to, though, I believe that https://github.com/makerbot/MightyBoardFirmware/tree/master/bootloader/8U2_firmware is the correct image for the vanilla 8u2 chips.

If you have a mainboard with an ATMega2560 processor and you changed the bootloader, that may be why it's not communicating. AIUI, the mega1280 and 2560 default bootloaders expect to be tickled at different baud rates. The 8u2 only uses one. So if it's a problem with a 2560 bootloader not responding use https://github.com/dcnewman/MightyBoardFirmware-2560-bootloader/tree/master/goodHexFiles

[Edmund]

I was able to figure it out. In the arduino folder are some .hex files. There is a "DFU and serial combined" one. Flashed that and then a device popped up in device manager. After that I just installed arduino drivers (believe that was the one) and it worked from there.
Hope this can help someone in the future cause it was a pain for me to figure out!