LinuxSA Mailing list archives

  From: Alan Kennington <akenning@dog.topology.org>
  To  : Richard Sharpe <sharpe@ns.aus.com>
  Date: Tue, 13 Jun 2000 20:58:33 +0930

Re: no boot at all -- I give up!

On Tue, Jun 13, 2000 at 10:33:37PM +0900, Richard Sharpe wrote:
> 
> I imagine that the BIOS is looking for the MBR signature, 0xAA55 in the
> last two bytes of the very first sector. Are they there? Perhaps they have
> been clobbered.
> 
> You should be able to use dd to get them off and od to display them.

Yes. I remember that trick from my SunOS days.
The result is a perfect AA55:

======================================================================
0000000 ebfa 006c 0000 494c 4f4c 0001 0014 016b
0000020 0000 0000 7e30 38f3 0011 8080 1201 8000
0000040 0180 0010 8080 0101 0000 0000 0000 1400
0000060 8000 0180 001e 1180 1f01 8000 0111 0020
0000100 1180 2101 8000 0111 0022 1180 2301 8000
0000120 0111 0024 1180 2501 8000 0111 0000 0000
0000140 0000 0000 0000 0000 0000 0000 0000 b800
0000160 07c0 d88e 068c 006a 3689 0068 1e89 006c
0000200 1688 006e 00b8 8e9a b9c0 0100 f629 ff29
0000220 f3fc eaa5 0098 9a00 8efa 8ed8 bcc0 b000
0000240 00b8 8e90 fbd0 0db0 57e8 b000 e80a 0052
0000260 4cb0 4de8 be00 0034 00bb fc10 89ad adc1
0000300 c289 c809 2074 e846 0043 0672 c381 0200
0000320 eaeb b050 e820 002a 8858 e8e0 0012 c031
0000340 c288 13cd cfeb 49b0 17e8 ea00 0000 9b00
0000360 c050 04e8 01e8 5800 0f24 3004 3a3c 0272
0000400 0704 ff30 0eb4 10cd 5ac3 5b59 f6c3 40c2
0000420 5474 e280 53bf 5251 08b4 13cd eb72 f088
0000440 885a 7316 8801 30f2 51f6 cd86 c5d0 c5d0
0000460 e580 8903 710e 5901 e183 f63f 01e1 93c8
0000500 f758 92f3 f1f6 c4fe 2688 0174 8892 8ad6
0000520 7316 3b01 7106 7701 8613 d0c4 d0c8 0ac8
0000540 7406 8901 5bc1 01b8 cd02 c313 315b f9c0
0000560 00c3 0000 0000 0000 0000 0000 0000 0000
0000600 0000 0000 0000 0000 0000 0000 0000 0000
*
0000660 0000 0000 0000 0000 0000 0000 0000 0180
0000700 0001 fe83 003f 003f 0000 3e82 0000 0000
0000720 0101 fe82 103f 3ec1 0000 ec10 0003 0000
0000740 1101 fe83 13ff 2ad1 0004 ff43 00bc 0000
0000760 0000 0000 0000 0000 0000 0000 0000 aa55
======================================================================

I can even see the partitioning info at the end:
83, 82, 83. So this means that the BIOS should have 
tried to execute the MBR (if this block 0 is what the MBR is).
And that means that the mini-program in the MBR must have returned
an error or something.
But there was message from the MBR to the screen.
It should have jumped to the code in /boot.
But it didn't even get to the first L of LILO.

Cheers,
Alan Kennington.

-- 
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