FormulaFlash ECU/TCU programmer will read and write VAG Simos 18.1 ECU in boot mode without problem.
Here is an example of a VW Golf Simos 18.1 ECU boot reading and writing.
Formula Flash will show you wiring diagram. Follow wiring to connect ECU with device
Quick Search Simos 18 ECU
Select model and ECU
i.e VW Golf Simos 18.1
It will do this ECU in boot mode.
Choose Boot mode and press OK.
Connect ECU
Read eeprom and save
Read flash and save
Upload eeprom file you desire to write, write EEPROM with FormulaFlash
Then write Flash.
Write eeprom and flash very fast.