Building on the work shared in the AL551 threads here and chrisgotboost's compression research, I've put together an open-source toolkit for extracting ZF 8HP TCU firmware from VAG flashdaten FRFs.

Key findings:
The ZF 8HP ODX method 0x22 encryption is a 19-byte repeating XOR:
Key: CyA2008ZFVAGtcuxsam
Hex: 437941323030385a465641477463757873616d

The XOR key itself reads as ASCII: CyA 2008 ZF VAG tcu xsam — looks like an internal project label. If anyone recognizes the CyA/xsam naming convention from ZF tooling, the method 0x01 AES key might follow a related pattern.

The compression (also method 0x22) is an LZSS variant with a 2047-byte window instead of the standard 1023. Inverted flag bits (0=literal, 1=reference), 5-bit count + 11-bit displacement. Verified with a 1,310,208 byte perfect match against a known-good decrypted block.

Confirmed working on 4G0927158 (A6/A7 C7) and 4H1927158 (A8 D4) families. The 8K0 (A4/A5 B8) uses method 0x01 which is actual AES — that key is still unknown.

The repo also covers DQ381 BL301 extraction (same SH72549 MCU) and documents where the AES key/IV is stored in the bootloader (BOOT offset 0x344/0x354) for anyone chasing the BL401 key.

All keys, decompression algorithms, and platform research in one place:

https://github.com/dspl1236/vag-tcu-tools

Credits to chrisgotboost for identifying the encryption type and compression format (topic: ZF8 AL551 Compression http://nefariousmotorsports.com/forum/index.php?topic=22625.0), projectLSaudiA4 for the AL551 memory map and Ghidra work(http://nefariousmotorsports.com/forum/index.php?topic=22488.0title=), and bri3d/VW_Flash for the FRF pipeline that made this possible.

If anyone has the method 0x01 AES key (8K0 family) or a BL401 DQ381 bench read, the repo has a contributing section. Happy to add support for other TCU platforms (DQ500, DL501, DL382) if people share what they know... if its already out there then I need todo more reading.

DL381 ( 0AW) и DL501 (0B5) tcus (with 01 compress/crypt mark) use 256-byte long table of values from 0 to 255 in swapped order.
It is some add/shift algo not XOR-ing.
The tables is different for both TCUs.

The same crypt method is used in TCUs with 11 compress/crypt marking of types DQ200/DQ250/DQ400/DL501/D382
but with additional compressing.
Interesting that DL800 tcu with fake AA-mark use the same method not AES.

There was some confusion regarding the fake tag. My fault. I was referring to the fake tag "11" in the mechanotronic firmware for the Audi R8 DL800/DQ500. that use AES decrypting, See for exmaple 4S0927155xx
Other DL800s like 4T0927109x with tag "11" are decrypted in the same way as other units with 11 using 256 bytes table and compress LZZ