Grub entry for OpenWrt on multiboot USB

Installing and Using OpenWrt
1

I'm trying to install OpenWrt on a multiboot USB stick and can't configure the correct menuentry

I've extracted openwrt-22.03.2-x86-64-generic-squashfs-combined.img.gz onto the 5th partition of a GPT disk and created the following menuentry:

menuentry "OpenWrt 22.03.2 - test "{
       insmod part_gpt
       insmod ext2
       set root=(hd0,5)
       echo 'Loading linux...'
       linux /boot/vmlinuz
}

There is an initial msg from OpenWrt but it almost immediately crashes and reboots.

Is a log of the boot process recorded anywhere? I should be able to access it by mounting the partition from elsewhere.

Is there any debugging facility I can use?

2

correct.

now, I haven't tried the combined myself, but are you sure the /boot and the / reside in the same partition ?

could always try to add root=xxxx here, noinitrd might also be needed.

nope

serial console, if you add serial=

3

I added PARTUUID and now it gets started but then hangs. There is mention read cache disabled, doesn't support DPO or FUA, then shows:

sdb: sdb1 sdb2 sdb3 sdb4 sdb5 sdb6 sdb7 sdb8 sdb9 sdb10 sdb11
sd 2:0:0:0: [sdb] Attached SCSI removable disk

and then is unresponsive apart from C-A-D.

4

if I remember correctly openwrt still isn't a fan of GPT.

5

I've managed to install it, or rather copy the root file system along with the boot directory to a GPT partition and it does actually start.

Why should OpenWrt not run once it starts?

It is actually on an ext2 partition. Would that cause it to hang?

6

default partition is ext4, ext2 FS support might not come with the kernel, but it's only a guess.

7

I have now manage to boot mfslinux - https://mfsbsd.vx.sk/

  • (based on OpenWrt 21.02.2) from a GPT partition so can't see any reason for OpenWrt distributed versions not to work
8

depends on what modules they've added to the kernel, doesn't it ?

but yeah, I would expect it to work, too.

9

I have found that a version of mfslinux which is based on OpenWrt 19.07.5 boots up just fine, but the only problem is that it uses initram.igz which is a compressed filesystem so I'm unable to install anything on it.
Should I expect to be able to decompress initram.igz and boot a normal filesystem? Would I need a different version of vmlinuz in such a case, and is there a way to single step through the boot process to see where it hangs?