VEMS V3.3 ECU, BMW E30 turbo M50, firmware 1.1.94.

ECU stopped operating after output-channel testing. VemsTune detects Boot Mode, Bad Marker (0x34).

Firmware Upload closes without progress. Firmware Verify remains at 0%. MegaLoader fails to synchronize.

Bootloader responds AVR34 to serial command S at 19200 baud.

Tested two separate USB-to-serial adapters on COM3 and COM4, both with identical results. Previous tuning communication worked normally.

Please advise how to recover firmware using the universal bootloader.
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