[Debburn-devel] Write iso/isohybrid on pendrive:problem

[antispammbox-debian]

Subject: Re: [Debburn-devel] Write iso/isohybrid on pendrive:problem


> Hi,
>
>> [with] debian-7.2.0-i386-lxde-CD-1.iso > /dev/sdb
>> [...] debian-live-7.2-i386-lxde-desktop+nonfree.iso
>> I can re-format the free space present on usb
>
> These two images have MBRs with partition 1 beginning at
> block 64 (= 32 KB). See e.g. output of
>  /sbin/fdisk -lu debian-7.2.0-i386-lxde-CD-1.iso
>
> They have obviously been created with xorrisofs options
> -isohybrid-mbr and -partition_offset 16.
>
>
>> When change file in to: isohybrid debian-7.2.0-i386-lxde-CD-1.iso
>
> ISOLINUX program isohybrid produces an MBR with partition 1
> starting at block 0. This overwrites the MBR produced by
> xorriso.
>
> There is not much other difference to be expected between
> the downloaded ISO and its state after the isohybrid run.
> So i assume this must be the cause.
>
> One may test this theory by setting byte 448 of the isohybrid
> result to 1 and byte 454 to 0. The ISO is prepared to work with
> that start address to. But program isohybrid did not know.
>
>
>> cat debian-7.2.0-i386-lxde-CD-1.iso > /dev/sdb
>> on pendrive, with filesystem ext2 or Fat32
>
> After that cat command, the filesystems are overwritten or at
> least unreachable.
>
>
> Have a nice day :)
>
> Thomas


Ok, many thanks!

Then isohybrid does not produce a true hybrid file, because once written, 
cannot re-format the space free on usb!?


But the problem then, is, how to create isohybrid file,  that allows  
to re-format free space on usb.


Thanks