Comment 110 for bug 1922342

Hi,

Chris Guiver wrote:
> └─sdb4 8:20 1 4G 0 part /media/guiverc/writable

So it seems that casper added its persistent partition without creating
a dummy MBR partition with boot flag.
This simplifies the task of making current Ununtu ISOs digestible for
the j3400. One run of

  dd if=/dev/zero bs=1 count=16 of="$STICK" conv=notrunc seek=462

suffices.

Chris Guiver wrote:
> guiverc@d960-ubu2:~/uwn/issues/735$ xorriso -indev /dev/sdb -report_system_area plain
> xorriso : FAILURE : Drive address '/dev/sdb' rejected because: not MMC and -drive_class 'caution' '/dev'

My mistake. The program is right. The command proposal should have been

  xorriso -indev stdio:/dev/sdb -report_system_area plain

Please run this to verify that the dummy partition is really not there
after the first successful booting of the USB stick.

(The demand for the "stdio:" prefix is a safety precaution to protect
system disks from dangerous superuser activities.
I forgot about it because i have a file /etc/opt/xorriso/rc which declares
  -drive_class harmless '/dev/sd[c-e]*'
so that i don't have to use "stdio:" with my USB sticks.
Whatever, -indev without -outdev to the same device prevents writing
and -report_system_area "plain" does not want to write to the device.
So it would be safe even for the system disks.)

Have a nice day :)

Thomas