You can? to make the passage read at boot and then write in the serial, otherwise I wouldn't know but it seems to me unnecessary and risky, in the sense that if you can read it in serial, it is convenient to write in serial without risking to open the ecu.
On the Marelli, which can be read on the serial line read in the boot, then? (with the original in hand) you can write to a serial port without the problems as many times as you want.