Hacking Nand erase downgrade

[Demix]

So phones have firmware like ps4, and to downgrade is to erase the nand and do an image restore. Why cant the same be done on an ps4?

 

[Mazamin]

Cause there are some things called e-fuses that get burnt when it gets updated, so for example 5.0.0 needs 5 burnt efuses, but if you restore 1.0.0, it won't boot cause there are more fuses burnt than needed (really fast and incorrect explanation but it's just to give you an idea)

 

[Hayato213]

It is possible for the future maybe but at the moment it is not possible, you need to get access to the specific encrypted key possibly to be the syscon key for the PS4, allowing you access to SAMU, the PS4 security processor for possible downgrade.

 

[smf]

So phones have firmware like ps4, and to downgrade is to erase the nand and do an image restore. Why cant the same be done on an ps4?

The technical method is complex, but the simple reason is that sony don't want you to downgrade your ps4 while the phone manufacturers don't care if you downgrade. Some phones let you unlock the bootloader so you can compile your own OS and flash it, Sony don't allow that on the PS4 either.

Sony don't want you to downgrade for the same reason that you want to downgrade, older versions have unpatched bugs. So they made the PS4 check.

It may be possible to find an exploit for that check, but it's not happened yet.

 

[ital]

Bring back modchips!

 

[KiiWii]

@Mazamin ps4 doesn’t use efuses.

Syscon stores version data (encrypted) in SNVS iirc.

@smf a CUH2DUH method would be ideal. Then upgrade and downgrade at will

 

[smf]

@smf a CUH2DUH method would be ideal. Then upgrade and downgrade at will

Do you think that is remotely possible?

 

[KiiWii]

Do you think that is remotely possible?

Yes I know it’s being looked into.

I know there are some other things in the works behind the scenes that could be truly game-changing.... if they work out.

Unfortunately no ETA