John,
Glad to give the exact steps that work for me. I have now used this to produce 5 or 6 bootable USB’s and the process is quite reliable for me.
One thing I have not successfully done is increase the size of persistent memory beyond the 4 GB size limitation. There are a number of posts different places with several methods for accomplishing this. However, I haven’t gotten any of them to work for me. However, I haven’t been able to spend much time on that. Perhaps someone can complement this post with some steps on how to increase the size of the persistent memory. That would be very useful now that larger USB drives are so inexpensive.
Getting Persistence
Although the UNetbootin process is supposed to result in a drive that has persistence, meaning it will keep changes and saved files between boots, this was not found to be the case on the HP Envy laptop used in this exercise. The reason is not entirely clear, although it may be due to different boot software and file formats used in different systems. Perhaps other combinations will work without a problem, but that wasn't what was found with this combination.
To enable persistence the 'grub.cfg' in the /boot/grub directory of the USB drive must be modifed. The word 'persistent' but the inserted before the 'file=...' in the places. See the resulting 'grub.cfg' file below with the addition highlighted.
Figure 3 - The grub.cfg file must be modified to enable persistence
if loadfont /boot/grub/font.pf2 ; then
set gfxmode=auto
insmod efi_gop
insmod efi_uga
insmod gfxterm
terminal_output gfxterm
fi
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
menuentry "Try Ubuntu without installing" {
set gfxpayload=keep
linux /casper/vmlinuz.efi persistent file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash --
initrd /casper/initrd.lz
}
menuentry "Install Ubuntu" {
set gfxpayload=keep
linux /casper/vmlinuz.efi persistent file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash --
initrd /casper/initrd.lz
}
menuentry "OEM install (for manufacturers)" {
set gfxpayload=keep
linux /casper/vmlinuz.efi persistent file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash oem-config/enable=true --
initrd /casper/initrd.lz
}
menuentry "Check disc for defects" {
set gfxpayload=keep
linux /casper/vmlinuz.efi boot=casper integrity-check quiet splash --
initrd /casper/initrd.lz
}
Best Regards,
Stephen Berger
From: John Petrich [mailto:address@hidden
Sent: Sunday, February 14, 2016 12:43 PM
To: address@hidden
Subject: Modified USB boot config
Stephen,
Read your post on Discuss GNU Radio about enabling persistence mode on a bootable USB stick Would you mind outlining the exact steps? Many of us are having the exact same problem that the Unetbootin persistence partition doesn’t persist.
Regards,
John Petrich