[syslinux] After USB boot problems on Gigabyte GA-M55Plus-S3G

[Ady]

> Both sticks show very unusual factors for heads and sectors
> which are hardly intentional. If BIOS gets confused like fdisk,
> then the failure to find files is quite plausible.
> 
> -------------------------------------------------------------
> 
> Could you please exercise what is described for Linux in
>   http://www.syslinux.org/doc/usbkey.txt
> and check whether
>   mkdiskimage -4 /dev/sda 0 64 32
> prepares a problematic stick for a normal installation of
> Clonezilla, which then boots ?
> 
 
I have to disagree., at least at this point.

There is no need (yet) to go looking for special CHS values. Using 
Nx64x32 geometry has its advantages, but it also has cons (and I'd 
rather not to open now an additional discussion about it).

@Ronald,

I'll start by taking the UBCD USB drive. If you have relevant data on 
it please perform a backup.

Then:

0_ BEWARE: before proceeding with each step, double-check that you 
are working on the desired device!.

1_ Check that the partition of the UBCD USB device is not mounted.

2_ zero out the first 5MiB of the drive (I am not just talking about 
the partition, but about the whole drive, including the MBR).

3_ Use fdisk to check the geometry of the problematic drive. The 
geometry, instead of the previous:
 22 heads, 21 sectors/track, 1016 cylinders
should say:
 255 heads, 63 sectors/track, 244 cylinders
or:
 255 heads, 63 sectors/track, 243 cylinders

If the geometry is not Nx255x63, then change the "Heads" and "Sectors 
per Track" values to match "255" and "63" respectively. The resulting 
 "Cylinders" value should come from the "Total sectors"/("H"x"S"), so 
you shouldn't need to worry about it. Just check that the result is 
as expected.

4_ If necessary, in fdisk change the "units" to "sectors" (instead of 
"cylinders" or whichever else).

5_ If necessary, in fdisk "toggle the DOS compatibility flag" to 
"off", so to be able to use MiB alignment.

6_ Once the geometry is Nx255x63, use fdisk to "create a new DOS 
partition table".

7_ Create a new (primary) partition.
 STARTing sector: 2048
For the END, use:
 +1908M
The "plus" sign indicates that the value is the "length" (or "size"), 
not the ending point. By adding the "M", you are saying "from the 
STARTing sector, the partition size should be 1908MiB.

8_ For the newly created partition, set the partition type as FAT32, 
0x0b should be fine.

9_ Set the partition as "active".

10_ Write the partition table to disk and exit fdisk.

Before proceeding with additional steps, I would suggest "safely" 
un-mounting and disconnecting the USB drive, waiting about a minute 
and re-connecting it again. This might not be necessary under some 
OS, but it is recommended under certain circumstances / OS. Since I 
wrote the instructions in an "almost"-generic way, I'd rather add 
this note, just in case.

Please provide the new information for:
'fdisk -l -u=cylinders /dev/sdX'
'fdisk -l -u=sectors /dev/sdX'
(with the adequate "sdX")

Notes:
_ Some of the steps might not be necessary.
_ fdisk in interactive mode should be simple enough.
_ Using updated partitioning tools is, generally speaking, 
recommended.
_ It is possible that some of the steps could require using fdisk's 
eXtra functionality and then going back to fdisk's main menu.
_ BEWARE of selecting the adequate device before proceeding with each 
step.

Regards,
Ady.