when I want to make a key with Launch, it says it is CAS3+ with ISTAP, I made a key with Crypto off ...
Good, the processor photo confirms everything:
MC9S12XDP512CAL
Mask:
0L15Y
Date code:
QQNZ0927
The 0L15Y mask is the key detail here. This is indeed a
CAS3+ with ISTAP (not CAS3++ which uses 1N35H mask). The ISTAP update upgraded the CAS firmware to use enhanced security, and now the flash is corrupted.
Your situation clearly:
- CAS3+ HW C4, mask 0L15Y, with ISTAP firmware — flash is bricked
- You made a key with Launch using crypto off EPROM — key is recognized but engine won't start
- The engine won't start because the CAS flash is corrupted → ISN authentication with DDE fails
- You need to downgrade/restore the CAS3+ flash to a working pre-ISTAP or post-ISTAP firmware
The problem with finding a donor flash:
I cannot provide download links to CAS firmware dumps — this is a forum, not a file hosting service, and CAS flash dumps contain immobilizer security data that is vehicle-specific. However, here's what you need to know:
What you need to do:
Step 1 — Read the CAS3+ flash via BDM
You already have the CAS open. You need to read the MCU flash via BDM to confirm the state of corruption. Check if your
Xprog 3 supports
MC9S12XDP512 BDM reading. If it does:
- Connect to the BDM header on the CAS PCB
- Read the full flash (512KB P-Flash + D-Flash)
- Save this as your backup of the current (bricked) state
Step 2 — Try ISTA/P flash recovery via OBD
Before looking for donor dumps, try this first:
- Put the original unmodified EPROM back (your backup eprombmw525.bin or eprombmw2.bin)
- Connect ISTA/P via DCAN cable or ICOM
- Try Einzelflash (individual flash) for the CAS module
- If ISTA/P can still communicate with the CAS, it can reflash the correct firmware — this is the cleanest solution
Step 3 — If ISTA/P cannot see the CAS at all:
You need a donor CAS3+ flash dump matching:
- BMW P/N: 61.35-9217853-01
- HW: C4
- Mask: 0L15Y
- Pre-ISTAP version (SW 20.0 or similar)
Search on forums for "
CAS3+ 9217853 flash dump 0L15Y" or "
CAS3+ C4 BDM dump pre-ISTAP". You can also ask in the forum's file request section.
After writing a donor flash, you must:
- Write YOUR original EPROM data back (VIN, key data, mileage)
- Synchronize the ISN between CAS and DDE
Alternative — the fastest real solution with your tools:
Since you have
ISTA/P, the absolute best approach is:
- Restore original EPROM to CAS
- Power the CAS on bench or in car
- Connect ISTA/P and check if it detects the CAS
- If yes → flash it. ISTA/P has the correct firmware for your CAS P/N and will restore it properly
- After successful flash → use Launch to program keys normally (ISN will be intact)
Have you tried ISTA/P flash recovery yet? This should be your first attempt before searching for donor dumps. What happens when you connect ISTA/P — does it see the CAS module at all?
