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BitLocker eGPU issue

When using a eGPU on windows, it might trigger a prompt to unlock bitlocker when booting.

To solve this:

Check if PCR2 Group Policy is enabled​

  1. Win + R > manage-bde -protectors -get c:
PS C:\WINDOWS\system32> manage-bde -protectors -get c:
BitLocker Drive Encryption: Configuration Tool version 10.0.26100
Copyright (C) 2013 Microsoft Corporation. All rights reserved.

Volume C: [OS]
All Key Protectors

Numerical Password:
ID: {...}
Password:
...
Backup type:
Microsoft account backup
AAD backup

TPM:
ID: {D67CDDC4-F473-478E-A5BD-E12884E5E4F8}
PCR Validation Profile:
0, 2, 4, 11
  1. Then check for "PCR Validation Profile" values

Disable PCR 2 and PCR 7​

  1. Win + R > gpedit.msc

  2. Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives

  3. Select "Configure TPM platform validation profileéfor native UEFI firmware configurations"

  4. Mark as "Enabled"

  5. In the options, disable "PCR 2: Extended or pluggable executable code"

  6. In the options, disable "PCR 7: Secure Boot State"

Rebind the TPM Protector​

  1. Delete the old TPM protector:
manage-bde -protectors -delete C: -type TPM
  1. Add the TPM protector again:
manage-bde -protectors -add C: -tpm
  1. Verify as described above.

  2. Reboot the machine with the eGPU connected, the system might flash some BIOS drivers.