It's not just EPYC, Lenovo makes heavy use of PSB (Platform Secure Boot) locking for their desktop/workstation machines too (TR or Ryzen Pro). The PSB feature i

It's not just EPYC, Lenovo makes heavy use of PSB (Platform Secure Boot) locking for their desktop/workstation machines too (TR or Ryzen Pro). The PSB feature is enabled by default so when installing a new CPU the user is prompted to lock it at every boot until the feature is disabled in BIOS. The locking is handled on-chip, it's permanent, and it leaves the CPU working only on the OEMs motherboard/BIOS. This poisons the used parts market. But worse, these systems are always just one BIOS update away from not booting the fused CPUs anymore (e.g. signing the firmware update with new keys). AMD included this in their CPUs because large OEMs like Lenovo and Dell asked for it. There's no extra security being offered by this feature, despite the OEMs throwing the word around every time to cover up it's only securing profit.