讨论:MS Asset:5362464

Reset Bitlocker

Is it possible to reset this device to factory settings? captainlinux8880（留言） 2024年3月7日 (四) 18:28 (CST)

It is possible. I can just format the system partition and install a new copy of Windows, or doing the factory reset in WinRE environment, but I don't need to 'cause I don't need another Atom tablet for use, also the performance of this tablet is not good. Probably I (or someone else) can get/calculate the Bitlocker password in BIOS ROM (I dumped the original ROM before batch a new one), then maybe the system partition could be unlocked. -WoodEar85（留言） 2024年3月8日 (五) 11:40 (CST)

你需要理解重置过程以及bitlocker的解锁流程。的确可以通过重置过程转储所需的VMK（CVE-2022-41099），但是这首先要求fTPM正常工作，但是显然经过固件重写之后fTPM对应的nvram已经不在了。--蓝色泪雨（留言） 2024年3月8日 (五) 13:17 (CST)

So that means, to unlock this BitLockered partition is almost impossible, only have a extremely tiny chance that the BIOS ROM contains the key (or some sort) than the partition can be unlocked. So, just RIP to the system partition. --WoodEar85（留言） 2024年3月8日 (五) 18:00 (CST)

It is impossible to unlock BitLocker without a key, which is why I suggested resetting the device to factory settings. We can also format the partition, but we need to preserve the originality of the system. captainlinux8880（留言） 2024年3月8日 (五) 20:28 (CST)

No use. The original BIOS ROM is corrupted, so I desoldered the BIOS ROM and batched a working *.BIN copy of BIOS ROM, then soldered it back to the board, and the tablet survived. But the BIOS rom is not the original, even if the BitLocker key is stored in the BIOS ROM，the new ROM doesn't contains it. — 以上是WoodEar85 (讨论 • 贡献) 的未签名留言。

As I know about Lenovo ThinkPad 8 tablet, it uses fTPM (Firmware TPM) not dTPM (Discrete TPM). If this tablet uses dTPM (like HP ElitePad 1000 G2), the BitLocker key is stored in TPM chip, so a BIOS and hardware swap will not take influence to the key, you only need the TPM chip working, the BitLocker can be unlocked. (even the motherboard is damaged severely, you can just buy a working motherboard, swap the TPM chip and the eMMC or SSD, then the BitLocker can be unlocked.) But fTPM uses NVRAM in CPU to store the BitLocker key (or extremely tiny chance that the key is stored in the BIOS ROM), a BIOS swap or important hardware swap will clear/rewrite the NVRAM and the key is lost.

Also, I tried to reset the device to factory settings before, but not work. So just say RIP to the data.--WoodEar85（留言） 2024年3月8日 (五) 23:02 (CST)

oh... :( captainlinux8880（留言） 2024年3月9日 (六) 00:41 (CST)