livecd-iso-to-disk.sh and MBR - livecd - Fedora mailing-lists

6 Jul 2013


      I built a bootable USB stick using:
sudo ./livecd-iso-to-disk.sh \
    	--format \
    	--overlay-size-mb 4095 \
    	--home-size-mb 200 \
    	--unencrypted-home \
    	Fedora-Live-Desktop-x86_64-19-1.iso \
    	/dev/sdi
The USB was a Kingston DT101 G2 8GB unit, fresh out of the package.  I
have no idea what Kingston loaded onto the MBR.  It has a single VFAT 
paritition with a few freebie Windows utilities.
It would not boot after running livecd-iso-to-disk (I had no reason to 
try booting it before).
So I did the whole thing over again with --reset-mbr
And then it worked.
I don't really understand when one needs to reset the MBR and when one
doesn't.  The documentation seems to suggest that one only needs to do
this when things have gone wrong.
This may be helpful in recovering a damaged or corrupted
    device.
My experience suggests that this isn't the complete story.
Is there a way of doing --reset-mbr that doesn't require redoing the
whole job of building a bootable USB stick?
Should --format imply --reset-mbr?
It seems that --format requires that the syslinux package be
installed.  Is it always installed or should the dependency be noted?
(When I learned about PC Master Boot Records, decades ago, they were a
clever bit of code that just loaded and branched to the boot record of
the first primary or extended partition that was marked with the
"active" flag.  The primary partition table was embedded in the MBR.
I guess it's no longer that simple.)