Dell Epyc 7742 - unlock

[VRuler]

Managed to get two 7742 at a decent price. The issue is these are Dell, not the retail version.


Couldn't find a solution, online, except getting a Dell system board. Anyone managed to make these work on a Supermicro/Asrock/Gigabyte motherboard?

 

[mach3.2]

As far as I know the only way around the Dell PSB lock is to get a Dell board. The processor basically rejects any BIOS not signed by Dell and stop the POST process, so you're SOL there.

 

[NablaSquaredG]

Except if AMD decides to release some kind of update, there is no way.

The CPU is physically (as literally burned into the silicon) locked to Dell. Forever.

 

[Leo Atreides]

I've heard that putting any retail 7742 into a Dell locks it. If that is so then it could be ( I am guessing ) a blown out capacitor on the backplane.

I dont think its on the silicon, that would require substantial additional investment.

 

[ari2asem]

@VRuler ....forget about it. dont' spend any second about how to get this working.

throw in the garbage. or sell it

 

[Patrick]

Sadly - https://www.servethehome.com/amd-psb-vendor-locks-epyc-cpus-for-enhanced-security-at-a-cost/

You need a Dell system.

 

[RolloZ170]

I dont think its on the silicon, that would require substantial additional investment.

AMD processors are shipped unlocked from the factory, and can initially be used with any OEM’s motherboard. But once they are used with a motherboard with PSB enabled, the security fuses will be set, and from that point on, that processor can only be used with motherboards that use the same code signing key. (Source: AMD statement to STH)

 

[jpmomo]

I am not so sure that this is a physical thing. I had a colleague that was doing some testing for amd and had gotten a few loaner cpus (7763 and 7713). He was also testing on some dell r7525s that were his own. He mentioned that amd was able to "reset" the cpus somehow when he was done testing and shipped them back.

 

[RolloZ170]

I am not so sure that this is a physical thing.

if AMD uses eeprom cells, its physical enough. your colleague is not under NDA ?

 

[jpmomo]

good point. in either case, there is nothing the end user can do once its locked.

 

[RolloZ170]

good point. in either case, there is nothing the end user can do once its locked.

do some remember the UV boxes to erase(logical 1 fill) EEPROMs ?

 

[bibi2023]

from reading https://www.servethehome.com/amd-psb-vendor-locks-epyc-cpus-for-enhanced-security-at-a-cost/
i think it is possible to try copy signature from a dell bios/bmc to supermicro, if the boot check only the signature, not verify the full bios, the workround will works. the full verify BIOS is too much slow.

 

[RolloZ170]

think it is possible to try copy signature from a dell bios/bmc to supermicro, if the boot check only the signature

the EPYC cryptographic processor validates the BIOS with the key/cert. if the BIOS is not signed with right key/cert that fails.
the vendor lock stores the Dell public key into the EPYC.