FAT32 Bootloader

[trinopoty]

First, use hex for the values, it's easier to understand.
In MBR formatted disks, only the first partition is set as bootable, this makes things a lot easier. The first partition resides at LBA 0x3F.

[iansjack]

First, use hex for the values, it's easier to understand.
In MBR formatted disks, only the first partition is set as bootable, this makes things a lot easier. The first partition resides at LBA 0x3F.

More misinformation, unfortunately. Any partition on an MBR disk can be set to be the active partition. And you can never assume that a partition will start at a particular sector; that's why you have a partition table.

[Brynet-Inc]

In MBR formatted disks, only the first partition is set as bootable, this makes things a lot easier. The first partition resides at LBA 0x3F.

Code: Select all

Disk: wd0       geometry: 60801/255/63 [976773168 Sectors]
Offset: 0       Signature: 0xAA55
            Starting         Ending         LBA Info:
 #: id      C   H   S -      C   H   S [       start:        size ]
-------------------------------------------------------------------------------
0: 00      0   0   0 -      0   0   0 [           0:           0 ] unused      
1: 00      0   0   0 -      0   0   0 [           0:           0 ] unused      
2: 00      0   0   0 -      0   0   0 [           0:           0 ] unused      
*3: A6      0   1   2 -  12269 254  63 [          64:   197117486 ] OpenBSD

Liar.

[Solar]

Liar.

"Never attribute to malice that which is adequately explained by stupidity."

[Firestryke31]

Could consider to align the stack by 4 by using 0x8002 instead of 0x8000

0x8002 % 4 != 0, so 0x8002 is not 4-byte aligned. 0x8000 is, though.

If you read the code, you will see that the first thing pushed is bx, followed by a bunch of 32-bit pushes. The stack is currently misaligned for the latter cases.

Sorry, like I said it's been a long time since I've even last seen the code (and I still haven't looked at it). If I were to need a FAT32 bootsector today I'd probably end up starting over from scratch. It wouldn't surprise me if I had made plenty of stupid mistakes in that code.