Eh it’s perfectly possible to write lock the ECU, but it’d be a pretty dumb thing to do since bricks would be impossible to recover without bdm (it’s also not difficult to bdm lock the cpu). To prevent “unauthorized” users from writing the ECU one could also theoretically change the security access keys, and I suppose increase the key width to 1024-bit to prevent factoring. Another option would be to fix the signature verification flaw and change the key to your own. Either method a bit of a dick move IMO since it would prevent the end user from going back to stock.
Oh and if anyone is interested, I wrote an msx70 reading / flashing program
https://nam3forum.com/forums/forum/m...pha#post221387
MSS70 xdf:
https://www.ms4x.net/index.php?title...#Siemens_MSS70
MSV70 xdf:
https://www.ms4x.net/index.php?title...#Siemens_MSV70
Xdfs courtesy of sda2
In theory my signature bypass shouldn’t break others, but tough to guarantee that so I always recommend starting from a stock binary. Eventually I’ll probably verify signatures of the program being flashed during a signature bypass to enforce that.