So i have been posting recently about trying to read my ecu via the obd2 yada yada, however i decided (since everyone said its not worth the work to try to do it via obd) to do it on the bench, could successfully read the file no problem. Read the file and tweaked it a little bit, checksummed with winols and with mpps v13. However when im trying to write the modified file to the ecu it stops at 21%, no problem writing back the original file (writing in boot mode). The chip on the board sits in a socket. So to my question, can i desolder the socket from the board and simply solder to chip to the main board without the socket, flash the original file on it and get it running properly, or do i need to flash an original C-box file, or what needs to be done to run the chip without the socket on the main board to be able to flash my own tune on it.

Yes, you can do that. But while you're at it, get a 1M ecu and switch to a better defined file if you intend to tune further