M1.x / M1.55 / M1.5.5
The early Motronic petrol generation — BMW E28–E36, Opel, and the transitional M1.55/M1.5.5 (Alfa Romeo, Opel Corsa C / Astra G).
| Era | 1987–2002 |
| File sizes | 32–128 KB |
| Variants | M1.3 (BMW ~1987–1993), M1.7 (BMW ~1989–1996), M1.55 (Alfa), M1.5.5 (Opel) |
| CPUs | HC11-era (M1.x), transitional (M1.55) |
Detection
Header magic or reversed-digit ident; M1.x generic fallback for bins with no explicit sub-variant string. Checksums: no family profile.