HP 6730b bios downgrade

[SzosszeNET]

Sorry, I'm a bit lost on some questions so did seem the right idea to post here...

So I have an HP 6730b laptop. It was running F17 BIOS (at least I think http://h20000.www2.hp.com/bizsupport/Tec...ob-90119-1) when I accidentally updated to F20 (that's sure - the current - http://h20000.www2.hp.com/bizsupport/Tec...b-102744-1)

And I wish to revert it. From windows that seems impossible :

/02/2012 17:36:53.187 FlashRomImage: set flash-in-progress successfully
10/02/2012 17:36:53.188 FlashRomImage(): Write Block #1, Attempt #1
10/02/2012 17:36:53.190 Start Write Flash Rom Image Block
10/02/2012 17:36:53.225 End Write Flash Rom Image Block
10/02/2012 17:36:53.237 FlashRomImage(): Write Block #1, Attempt #1 FAILED, error code = 0x15
10/02/2012 17:36:53.237 Cannot flash block #1 because it is blocked by BIOS. dwErrCode = 0x15
10/02/2012 17:36:53.238 FlashRomImage: Failed to write block #1 to Flash ROM. dwErrCode = 0x15
10/02/2012 17:36:53.239 Flash Image failed: lBytesLeft = 2097152, dwOffsetLocation= 0, bStatus = 0
10/02/2012 17:36:53.240 Start Clear Flash-In-Progress
10/02/2012 17:36:53.266 ClearFlashInProgress(): passed. hr = 0x0, dwRetCode = 0x0
10/02/2012 17:36:53.267 End Clear Flash-In-Progress
10/02/2012 17:36:53.268 End Flash Rom Image (Write), bStatus = 0
10/02/2012 17:36:53.269 End flashing (Write) Attempt #1
10/02/2012 17:36:53.269 Flash Rom: Cannot downgrade, BIOS blocks it - Error code = 0x15
10/02/2012 17:36:53.270 ***** END FLASHING PROCESS *****

I know the "cannot downgrade" rings bells, but I know that there must be a way.

Tried the BIOS restore method at boot (Win+B or four arrows) what I get is black screen and flashing "CAPS LOCK" light. But besides nothing happens for long minutes - an hour... (Before you ask had no HP tools partition, but restored it via HP BIOS UEFI Update). Also tried to restore it to USB. Copied the rom.bin+rom.sig to previous folder.
Any other clues?

Thanks.

[TheWiz]

Hi there,

Unfortunately the links you referenced didn't copy right.

http://h10010.www1.hp.com/wwpc/us/en/en/...html?dnr=1

Have you identified the BIOS brand beyond it being UEFI. It is possible you could try a DOS based UEFI flasher or a windows flash program to flash the BIOS independently of the HP software package, however you need to ensure it is the right flash method before flashing your computer, especially considering it's a laptop.

Regards,
TheWiz