-----Original Message-----
From: kunijadar shivanand(ＴＳＩＰ TMIEC ODG Porting)
Sent: 27 January 2023 12:50
To: cip-dev@...
Cc: jan.kiszka@...; 38A5323E673042E40E350B6BD8E7D4A7 <kazuhiro3.hayashi@...>; dinesh kumar(TSIP TMIEC ODG Porting) <dinesh.kumar@...>; pyla venkata(TSIP TMIEC ODG Porting) <Venkata.Pyla@...>
Subject: SWUpdate with unified-kernel using UUID in the kernel command line

Hi CIP-team,

I'm trying to use UUID in the kernel command line for selecting the boot target(rootfs) with unified-kernel image.
Check the below details on how UUID is used to switch the partitions and let me know what is the advantage of the initramfs script approach over UUID?

* Use filesystem UUID to specify the boot target (rootfs)
* UUID is generated for each filesystem and its value changes every release.
* Each unified kernel image is always generated with root=UUID=(The UUID of corresponding filesystem) in its cmdline and .swu includes the pair of unified kernel and rootfs.
* Install the update image using raw update type (i.e. block level).

Example:

Before update, Active partition: ROOTFS-A(mmcblk1p4):
sudo blkid
/dev/mmcblk1p4: LABEL="ROOTFS1" UUID="U1" TYPE="ext4" PARTLABEL="ROOTFS1" PARTUUID="PARTUUID1"
/dev/mmcblk1p5: LABEL="ROOTFS2" UUID="U0" TYPE="ext4" PARTLABEL="ROOTFS2" PARTUUID="PARTUUID2"

While building .swu
.swu includes...
a partition image (for ROOTFS-X) which UUID is U2 a unified kernel which cmdline includes root=UUID=U2

While installing the .swu for ROOTFS-B:
Unified kernel is installed to BOOT-B(mmcblk1p2) The partition image is installed to ROOTFS-B(mmcblk1p5)

After update, Active partition: ROOTFS-B(mmcblk1p5):
sudo blkid
/dev/mmcblk1p4: LABEL="ROOTFS1" UUID="U1" TYPE="ext4" PARTLABEL="ROOTFS1" PARTUUID="PARTUUID1"
/dev/mmcblk1p5: LABEL="ROOTFS2" UUID="U2" TYPE="ext4" PARTLABEL="ROOTFS2" PARTUUID="PARTUUID2"

Thanks & Regards
Shivanand K