Looks good, although I prefer labels.
UUIDs can be the FSs or the partitions… it gets confusing. The syntax is root=PARTUUID= for partitions. I do not know which one you’ve got.
As for uboot-update, I never used it nor do I have any idea what it does. I assume it’s a random non-standard script someone wrote.
My entry looks like:
label Arch-cwt9-rvalles
menu label Arch Linux 5.15.2-rt20-cwt9-rvalles
linux /boot/vmlinux-5.15.2-rt20-cwt9-rvalles
initrd /boot/initrd.img-5.15.2-rt20-cwt9-rvalles
fdtdir /boot/dtbs/
append root=LABEL=arch-root rw console=tty0 console=ttyS0,115200 earlycon rootwait stmmaceth=chain_mode:1
On blkid, the partition looks like:
/dev/nvme0n1p2: LABEL="arch-root" UUID="54267cf7-aa6c-4107-b9db-e16ca639d770" BLOCK_SIZE="4096" TYPE="ext4" PARTLABEL="arch-root" PARTUUID="915706c8-c4df-440a-9092-bf9cb2f7eb9d"