Information
PCR 2.1 were installed on various vehicles group VAG diesel engine 1.6TDI requires BSL unlocking.
Please note: where available real reading, only the calibration area is subtracted (not the full dump), in this case, pay attention to the version of the calibrations coincided with the current version of SW, otherwise. Work very carefully, only SIMOS 8.1/8.2 ECU can be restored via module 53 (Tricore BSL). The rest will have to change to new ones.
The current lock status is displayed when the unit is identified (works for SIMOS 8.4, 8.6 and PCR2.1):

Module: VAG: 2.8L V6 FSI (SIMOS8.6)
Identification
Catalog number: 4G0907552F
Software version: 0005
Hardware number: 2.8l V6 FSI CHVA
VIN number: WAUZZZ4G3BN******
Encoding: 1A250034042601020000
Programming: 2
ECU type: SIMOS8.6
The digital signature verification check: Disabled

If the check is disabled, you do not need to unlock it.
The essence of the unlock-modification of the external EEPROM installed in the unit. So before unlocking it is suggested to read EEPROM and save.
For ECUs PCR2.1 loader displays the current lock status when identifying in BSL mode (if set).

Serial number: 41048482-19E0A315-82060010-240EFE00
Hardware number: EV_ECM16TDI
Part number: 03L906023KN
Software version: 9056
VIN number: WAUZZZ8X4BB******
The digital signature verification check: Disabled
Serial number: 41848480-13C09713-82160010-270A0700
Hardware number: EV_ECM28FSI
Catalog number: 4G0907552F
Software version: 0005
VIN number: WAUZZZ4G3BN******

Each press of the “Initialization”button in BSL mode changes the lock status to the opposite. So be careful what you do.

How to work with ECU that require unlocking (PCR2.1)

1) Check the current lock status in the car, if the check is disabled, you can go to read-write, otherwise follow the instructions
2) Remove the unit from the car, open it, transfer the processor to BSL mode using the connection pictured (PCR2.1,) the work as a whole as in the package 53
3) Choose “PCR2.1 (EEPROM/UNLOCK/BSL)”
4) Click Identification – save ECU data somewhere in a text file.
5) Click Read – save the EEPROM
6) Given that ECU is blocked, we perform Initialization once for PCR2.1 get something like this displayed):
Module initialization
Entering programming mode
Transfer bootloader
Examination
The digital signature verification check: Disabled
Done
On this ECU BSL complete. remove resistors, and ECU can be sealed closed and put in the car. Then read write as normal