Custom remastered install image on a thumbdrive...

Question

I work on a LOT of PCs in my profession. I see everything from Arch, to windows, to ubuntu. I want a thumbdrive with all my tools on it that works easily from each and all platforms even as a instant recovery cd. to do this I want to load arch into an ext3 partition at the back of the thumbdrive and keep it bootable, and then at the front I want a vfat partition that can be loaded in windows. because this is a "removable device" windows will only ackoledge the first partition so it has to be fat. If I load arch into an ext partition at the end of the drive, it all works fine, except there is that little problem if writes on a flash drive... trying to alleviate that causes more and more and more frusterations.
enough!
so here's the idea... what if I dump the contents of the arch install disk onto a 10 GB ext3 partition at the end of the flash drive as previously planned, and load it as if it was an ISO imaged to the drive? well heres how far I have gotten:
boot to arch install disk on a PC with no drives but the CDrom, and the thumb drive attached. no HDDs.
partition the flash drive thusly:
cfdisk /dev/sda:
Name Flags Part Type FS Type [Label] Size (MB)
sda1 Primary vfat [MVUTILITIES] 52000.00
sda1 Primary Linux [ARCH_201308] 8000.00
sda1 Primary vfat [ARCHISO_EFI] 64.00
next format/name the partitions (though it shows above, no I did not label them in cfdisk) thusly:
# mkfs.vfat /dev/sda1 -n MVUTILITIES
# mkfs.ext3 /dev/sda1 -n ARCH_201308
# mkfs.vfat /dev/sda1 -n ARCHISO_EFI
now I get to mount the ISO and copy the contents!
# mkdir /mnt/stageing
# mkdir /mnt/archiso
# mount /dev/sr0 /mnt/archiso
# cp -a /mnt/archiso /mnt/stageing
# umount /dev/sr0
# mount /dev/sda2 /mnt/archiso
# cp -a /mnt/staging/archiso /mnt/
# umount /dev/sda2
# mount /dev/sda3 /mnt/archiso
# cp -a /mnt/staging/EFI /mnt/archiso
# cp -a /mnt/staging/loader /mnt/archiso
# umount /dev/sda3
# reboot
and this is where I'm stuck.
if the arch install CD is in the CD drive and I boot, the system loads the boot image from the cd but loads the squashfs file from /dev/sda2 (which is labeled ARCH_201308) so I get this nice little hybrid boot in which the CD is only necesary for the first loading then can be removed with no ill affects. Additionally, it is EASY to just install arch into the ext3 partition and boot, it works fine! so I know what I want to do is technically possible. can someone direct me to the next step?
what do I need to do to get a boot loader onto my thumb drive which will act EXACTLY like the original ISO did, but where the disk image is located AFTER a viable vfat partition?
UPDATE: Well that was fun... I figured out if I image the drive thusly:
# dd if=/dev/sr0 of=/dev/sda
then repartition the drive thusly:
cfdisk /dev/sda:
Name Flags Part Type FS Type [Label] Size (MB)
sda1 Primary Free Space 34.93 <--NOTE!!!
sda1 Primary vfat [MVUTILITIES] 52000.00
sda1 Primary Linux [ARCH_201308] 8000.00
sda1 Primary vfat [ARCHISO_EFI] 64.00
NOTE: there WAS 2M free space and a 32M vfat partition I just deleted the vfat AFTER adding MVUTILITIES and left it as is.
then followed the rest of my notes above... the thing actually worked!
but still, there _has_ to be a better way
Last edited by rudepeople (2013-08-10 02:24:25)

Answer 1

With USB, the archiso does not make an image that is able to be dd'ed to a thumbdrive and still be UEFI compatible.  To do this, you have to create a FAT32 partition, and then copy the contents over to the partition.  Then enusre that that name of the filesystem matches that of what is sepcified in the gummiboot configurations.  This is typiaclly ARCH_201308 or similar, though this can be specified with a cunstom archiso.
See the wiki page on UEFI (towards the bottom) for more info on how to create a UEFI bootable USB.
You may have to either carry two USB's or create two separate partitions on the USB... though I imagine that you could also just slap the necessary parts into the existing FAT partition you are already making in the beginning og the USB.
Edit: Okay apparently I didn't read the whole first post.  You do have these separate partitions already.  In this case, you need to ensure that the VFAT archiso partition is named what is specified in the \loader\entries directory.  Since you already have a dd'ed archiso on the USB, you are probably going to have to create a custom archiso with a different name, so that the filesystem names can be different.
Last edited by WonderWoofy (2013-08-10 04:05:05)