Yes you are right, it is not for switching between µSD and USB, its for eMMC. My bad.
To rule it out, could you try the Bullseye image from Armbian: https://www.armbian.com/odroid-xu4/
Very strange that old and new image fail to boot since the old one did work for years for others and the new one is quite different and did work for at least some users (you are the first who reports boot issues with it) 
. As if it’s something with the Hardkernel bootloader and/or kernel (source) itself. Which kernel version does Arch ARM ship with?
Here is the official Hardkernel Ubuntu image which shares mostly the same kernel, though not the same build: https://wiki.odroid.com/odroid-xu4/os_images/linux/ubuntu_5.4/ubuntu_5.4
You don’t have a UART adapter, do you?
Thank you for the answer Michalng!
I tried that Armbian image (funny how I was about to try that next), and unfortunately same thing occurs.
Not sure what that says about this problem, but I think my XU4 might have an issue.
The ArchLinuxARM kernel I use on this:
$ uname -srm
Linux 4.14.180-3-ARCH armv7l
Unfortunately I don’t have that adapter. I’m guessing it’s not possible to get more info on what’s happening without it?
In that case I’d either have to try out buying a new uSD card (if by the slim chance all uSD cards I tried were faulty), or to buy that adapter.
As it’s Linux 4.14, I’m quite sure it’s the older Hardkernel Linux sources, used in our previous XU4 image as well. Still no hint why it boots while our old one that you tried first does not .
Last thing you could try is the official Hardkernel Ubuntu image linked above and if it fails as well, report at Hardkernel forum: https://forum.odroid.com/viewforum.php?f=95
Probably someone there has a good idea what else to test/how to debug.
In /boot/boot.ini (on ext4 filesystem, so not directly accessible from Windows) or can downclock the RAM and change the initial CPU governor to reduce initial power draw, as a last idea I have.
same here flash install and now won’t boot
You need to update kernel to 5.4 it’s not a power adapter problem , Just install ubuntu mate 20.0.4 and update kernel 
Should be pretty similar to our new XU4 Linux 5.4 image then 
.
Thank you, however I’ve tried Hardkernel’s Ubuntu image, and it doesn’t boot from that one either 
It’s possible that I’m having some issues with the uSD cards or the card readers (even though I’ve used multiple of them), I’ll have to buy new ones and try with those instead.
Is there a specific thing I need to do to update the kernel?
As said, our image ships with the latest kernel already.
We however found another issue with the entropy daemon which might even be the reason why you don’t see the XU4 on network. I’ll generate a new image on a few hours to test first.
You’re right we have the same issues , if dietpi fail to boot up then Ubuntu 20.04 and 22.04 won’t boot up too , you can try flash ubuntu mate 18.04 or android image from www.hardkernel.com and see if boot up or not , i don’t think it’s the micro sd card/card reader or device hardware problem .
maybe some legacy stuff is needed that is shipped with Ubuntu 18.04 but missing on newer version?
I don’t know i tried flash other OS like OGST and Android / Android TV with no problem to boot and run so 100% not power adapter ( i have orginal adapter and 6a adapter )or device hardware problem , and i have zero problem running dietpi before bullseye image , now if i want to make dietpi bullseye boot again on XU4 i have first run ubuntu 18.04 on other micro-sd/emmc then upgrade 20.04 from 18.04 . then unplug the 18.04 microsd and then flash back dietpi bullseye on another emmc , it boot up but not last longer and cause many error .
same problem like other user ’ andoru ’
would it be possible to stick to a single post and not to communicate the same in 2-3 other post? This is not helpful. It is confusing to follow all the different strings. Let’s keep all information together on 1 post. Otherwise it is hard to follow for others.
Not that different kernel versions and boot configs can indeed consume different amount of power during boot. We had several cases where a kernel upgrade revealed an (before only close to) insufficient PSU. So that is not ruled out.
What somehow indicates any kind of hardware issue (PSU, cable, SD card/eMMC, attached peripheral/USB devices, or the SBC itself) is that the new official Ubuntu images fail to boot as well. If DietPi and Armbian were the only ones to fail, I wouldn’t have wondered, since there have been quite some cases where Armbian kernel upgrades broke things, but the Hardkernel images, used by a lot of users, are unlikely affected by the same bug. Another indicator for this is that it sometimes succeeds booting, sometimes not, so obviously there is no general issue with the image, like a faulty boot config, missing or invalid file or such.
You do not have a UART adapter to watch early boot messages, do you?
New images are btw up with haveged pre-installed instead of rngd, resolving at least the hanging Nextcloud installation.
Tried new image it boot up this time but it’s hanging during the installation , flash different emmc and micro sd still the same , when it load up to systemcrl-unmask command line it blue led gone and xu4 stop .
but atleast the image boot up this time
With hanging you mean crashing (since the SSH connection was lost)?
At least we are sure now the boot issues are not due to missing entropy.
Can you access the ext4 filesystem externally (from another Linux system e.g.) to enable persistent system logs?
The blue led stop and the OS stop also , now i also having problem to boot from armbian , i double check everything and trying to recover eMMC bootloader using this official method , Both eMMC works so i don’t really know why i cannot boot ubuntu 22.04 armbian and dietpi but any other OS works .
I mean i cannot boot Ubuntu 22.04 directly i must install 18.04 then upgrade to 22.04 , I also tried install Armbian bullseye it won’t boot up too no matter eMMC or micro-SD
Edit : Just recovery eMMC bootloader it seems works again with Dietpi Bullseye , Installed Nextcloud without hanging like before , but i will keep my eyes on if there any auto shutdown again .
Edit : Is that a reason why it works again ? because new U-Boot config requires a single ext4 partition without a dedicated boot partition. After recovery eMMC bootloader i can boot the new dietpi image . This makes me think it’s partition problem and that’s why xu4 refuse to boot the new dietpi image
Coming back on this thread after a hiatus.
Tried to boot Hardkernel’s Ubuntu 18.04.3 (20190929) as was suggested earlier, but it doesn’t even boot that. Tried both the full and minimal images. Also tried the Android 4.4.4 (v7.1) image, all of them produce the same result.