HP 6735b F.20 => flashback to F.15 or earlier possible?

[floppydev]

Hello,

I made a great mistake and flashed the HP 6735b from F.0A to F.20. Now it isn't stable any more. Is it possible to flash it back to F.15 or earlier?

I even tried to flash with modified flashing program (some blocks fail to write) via CDROM boot and via USB recovery without success.

Any ideas how this might be possible?
Can someone explain how flashing older BIOS is prohibited (I read with RSA signing)?
But on lower level a flash is just a very basic block device. How are the blocks protected and reopened on flashing e.g. a newer which might be released (e.g. F.21)?

You can be very, very technically on hardware and on software side (including ASM).

Thnx.

cu
floppydev

[floppydev]

No one has an idea?

cu
floppydev

[akuma6099]

No one has an idea?

cu
floppydev

You can flash back to any previous version. This requires disassembly and removal of your BIOS SPI flash chip. You must program it using an external programmer. Come back when you have a SPI programmer and are able to de-solder your flash chip. Then I can help.