USB Compatible BPB Issue

BenLunt · **Posted:** Fri Oct 27, 2017 8:26 am

mikegonta wrote:

A simple rearrangement of your ext2_hd.asm costs only 5 extra bytes (out of the 25 spare bytes that you have) to implement a self referencing MBR.

To follow my conclusions, you need a BPB in there too. Plus, my ext2 code is still incomplete, it needs a little bit more. Anyway, you get the idea.

Thanks,
Ben

BenLunt · **Posted:** Fri Oct 27, 2017 8:28 am

Octocontrabass wrote:

BenLunt wrote:

I created a UEFI partition type boot and changed the "Insyde" machine back to UEFI. It booted my USB Thumb Drive until the point it said that my loader is not certified. :-)

Caught by the TPM (Trusted Platform Module).

You created a partition? I wanted to know what it does when the disk isn't partitioned at all.

No. I did not try that. However, since it will have a valid MBR and Partition Table, I can pretty much guarantee that it will at least see it and add it to the boot options.

Octocontrabass wrote:

BenLunt wrote:

As for zeroing out the Thumb Drive and seeing if WinXP will partition it, that's a negative. WinXP sees the whole thing as a removable media device and a single partition containing the whole device capacity.

Diskpart's clean command doesn't zero the disk, only the partition table. It also sets the 0xAA55 signature if that's not already present. I don't know if that makes a difference to XP, but it does to 7.

I completely zerod out the whole drive. I didn't leave a 0xAA55 at offset 511. Something to try.

Thanks,
Ben

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USB Compatible BPB Issue

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