Just to help in case someone got in some like this

Had an 8L S3 here yesterday, used old ole MPPS:

- read by OBD OK, try to write with MPPS but it stuck in 800C...

- take fuse off and try again, and again stuck in 800C...

- try with old 1260 Galetto and it said it cant erase flash.

take ECU out and find an "no-AMD" 29F800AB there.

Even boot mode didn´t work either, had to desolder and after putting an AMD29F800BB there it back to work by OBD