Your message dated Wed, 28 Oct 2009 23:30:37 -0400
with message-id <[email protected]>
and subject line Re: Bug#552753: dosfstools: syslinux issues msg "Boot error"
due to incorrect FAT superblock fields hidden sectors and drive number
has caused the Debian Bug report #552753,
regarding dosfstools: syslinux issues msg "Boot error" due to incorrect FAT
superblock fields hidden sectors and drive number
to be marked as done.
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Bug report if necessary, and/or fix the problem forthwith.
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552753: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=552753
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Package: dosfstools
Version: 3.0.6-1ubuntu1~ppa2
Severity: normal
After reformatting, a usb-stick syslinux is now failing with an error
message of "Boot error" whereas it had been booting ok. This message
means that the syslinux ldlinux.sys program is not loading properly--the
first sector, which resides in the boot sector is loading but is not finding
the rest of the ldlinux program where it expects it. See Ubuntu
LP #398241.
I narrowed the problem down to the drop of 14-bootcode.dpatch. My BIOS
only recognizes a FAT hard disk file system if the drive number is 0x80
and hidden sectors is non-zero. 14-bootcode.dpatch was applied per
Debian bug report #303442 and was removed due to #489292.
According to the bug reporter for the latter bug the problem was in the
setting of the hidden sectors field in the DOS superblock (first sector). The
first fix set this so that the boot load program would think that it
was located in the first sector of the second track--a common case but
certainly not a universal one. This change broke booting from floppies.
The drive number should match the contents of DL for the INT 13 BIOS
call. The hidden sectors is used by some boot sector programs to find
where it is located on the drive, and therefore at what sectors the rest of
the contents of the file system can be found. (With hard disks the
combination of the MBR and a boot sector program can use the partition
table for the bootable partition rather than the hidden sectors field,
making the file system relocatable).
I suggest that the fix be restored but that the hidden sectors field be so
set only in the hard disk code section--and that it should be set from the
start field from the hard disk geometry ioctl result. It is my understanding
that this is what this field is for. The hidden sectors field should remain
zero for floppies, floppy images, and for any file systems starting at the
first sector of the device.
The FAT superblock settings I propose match what I observed in these
fields in dumping a partition formatted by one the original vendor's
reference operating systems.
I have coded a patch for the above, adding printing of these fields when in
verbose mode, and adding options to override the drive number and FAT
media byte. The patch does not include the original function to insert
bootcode.
>From the patch I have built a new version in my launchpad ppa
(http://ppa.launchpad.net/~jsjgruber/ppa/ubuntu karmic main)
In testing my version I found that test code included in Debian #489292
works as expected.
If you might be interested in the patch please let me know where I can submit
it for
thorough review.
-- System Information:
Debian Release: squeeze/sid
APT prefers karmic-updates
APT policy: (500, 'karmic-updates'), (500, 'karmic-security'), (500, 'karmic')
Architecture: i386 (i686)
Kernel: Linux 2.6.31-14-generic (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages dosfstools depends on:
ii libc6 2.10.1-0ubuntu15 GNU C Library: Shared libraries
dosfstools recommends no packages.
dosfstools suggests no packages.
-- no debconf information
--- End Message ---
--- Begin Message ---
This is a duplicate of 552673. Sorry, but I submitted it twice by accident. I
thought the first had an SMTP error. I apologise.
--- End Message ---
