2020-11-24
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Clemens Buschmann sent me this email, useful manual instructions for frugal
install when running any Linux distro, and configure grub2...

Hallo Barry, with reference to
https://easyos.org/install/easy-frugal-installation.html
last chapter "Manual steps", I wrote down a few additional / more up-to-date -steps:
feel free to adjust and publish them on the above website. Btw, thank you for this
awesome easyOS!

assumption: have a linux installed and running in bios (MBR) ext4 -partition /dev/sdc3 with 10, better 15 GB free space:

* $ ls -la /dev/disk/by-uuid/ | grep sdc3
lrwxrwxrwx 1 root root 10 23. Nov 11:00 b80c1ef6-51a8-4c34-a992-62062a1a83c4 -> ../../sdc3
* grab the latest easyOS -image, e.g.
$ cd downloads/iso
$ curl -O http://distro.ibiblio.org/easyos/amd64/releases/buster/2.5/easy-2.5-amd64.img.gz
$ gunzip easy-2.5-amd64.img.gz
continue as root: $ su -
# cd /home/xyz/downloads/iso
# fdisk -lu easy-2.5-amd64.img
* gives something like
Disk easy-2.5-amd64.img: 1.3 GiB, 1343225856 bytes, 2623488 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x7d9b2937
Device Boot Start End Sectors Size Id Type
easy-2.5-amd64.img1 * 2048 1310719 1308672 639M ef EFI (FAT-12/16/32)
easy-2.5-amd64.img2 1310720 2621439 1310720 640M 83 Linux

* assuming you are using bash -shell, you'll want to mount the first (vfat) -partition with start sector 2048:
# mount -t auto -o loop,offset=$((2048*512)) easy-2.5-amd64.img /mnt/loop
* create and populate the easyOS directory:
# mkdir /boot/easyOS
# cp -i /mnt/loop/easy.sfs /boot/easyOS
# cp -i /mnt/loop/initrd /boot/easyOS
# cp -i /mnt/loop/vmlinuz /boot/easyOS
* create your customized initrd:
# cd /boot/easyOS
# mkdir initrd-tree; cd initrd-tree
# cpio -id < ../initrd
# ls -la
* apply changes to BOOT_SPECS with your favourite editor, in the above case:
BOOT_UUID='b80c1ef6-51a8-4c34-a992-62062a1a83c4'
BOOT_DIR='boot/easyOS/'
WKG_UUID='b80c1ef6-51a8-4c34-a992-62062a1a83c4'
WKG_DIR='boot/easyOS/'
rm ../initrd
# find . | cpio --create --format='newc' > ../initrd

* include easyOS in Grub2 -bootmanager, appendig the following to /etc/grub.d/40_custom (adjust to your environment!):
menuentry "boot easyOS from boot -subfolder on sdc3" {
insmod part_gpt
insmod ext2
insmod search_fs_uuid
search --no-floppy --fs-uuid --set=root b80c1ef6-51a8-4c34-a992-62062a1a83c4
linux /boot/easyOS/vmlinuz ro rd.plymouth=0 plymouth.enable=0 vt.default_utf8=1 acpi=strict loglevel=3 \
root=UUID=b80c1ef6-51a8-4c34-a992-62062a1a83c4 rootfstype=ext4 noresume
initrd /boot/easyOS/initrd
}
# update-grub
or, depending on your distribution
# grub2-mkconfig -o /boot/grub2/grub.cfg'

* leave, delete or compress the downloaded easyOS -image, e.g.
# umount /mnt/loop
# exit
$ xz easy-2.5-amd64.img

An update rather than a fresh install should work very much the same, just (after backup!) delete
/boot/easyOS/vmlinuz /boot/easyOS/initrd /boot/easyOS/initrd-tree/* /boot/easyOS/easy.sfs
while in your original linux -environment