Boot Order difference between Ubuntu and Debian

I thought radxa boot order is sd-card and then eMMC. So when I install Ubuntu image on sd it boots up ubuntu, but when I install Debian image on sd-card it boots from my eMMC card (there is Armbian image installed). Images on sd-card are written with windows etcher. Image on eMMC card is written with dd command on Rock Pi. Any info why boot order with debian is different than ubuntu.
Thanks Norbert

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My Debian boots from SD first, have 2 micro SD cards all the same, all flashed with etcher.

The boot order has not caused confusion for the first time. :wink:

I guess the chance is your SD card image doesn’t have the correct boot partition so Rock Pi skipped it.

Just tried again and it works. Booting Ubuntu from sd when inserted. Don’t know why it did not work last time. I also did get my M2 extender today and it works fine with my samsung. I had to order longer connection cable so I can change sd when M2 Board is installed. When everything is ready I will try the different images.

I’d check if inserted the microSD card in the right direction, make sure the connector side always face the circuit board.

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Yes, I noticed a change in boot order when I upgraded from Debian armhf to the recent build of Debian arm64. Prior to the upgrade, I could boot from uSD (then mount the SSD to extract an image onto eMMC, overwriting the existing OS). Now, the 64 bit build ignores the uSD and USB during boot up.

Shouldn’t there be a subroutine at the beginning of the boot process that checks for bootable removable media, prior to loading the OS from eMMC?

In my experience seems to be related to the microSD card, if I had the fastest SanDisk in, it will always boot from there. If I had the slow PNY card in, the booting sequence seems to be random :smiley:

I have the fastest SanDisk and the booting sometimes is still random

You nailed it again! It was the uSD, even though I have always purchased the fastest Class 10 SanDisk media.
Waliworld only had more of the same… except for one PNY uSD that was rated for 4K video. So, I figured I had little to lose and it worked!

Thanks !

BTW, is it possible to replace an OS that’s currently running? That’s a no-no in Windowsland w/o rebooting into a another OS as part of the process.

I believe (which mean I can’t prove it) it’s the “boot loader” - which is comparable to BIOS in PC, resides in the on-board flash and loads u-boot from eMMC/microSD has a short timeout setting, it gives that much time for microSD to boot, or goes to eMMC if microSD doesn’t respond in that period of time. The pricier microSDs got shorter latency.

But if you reboot while the microSD is still “hot”, it will response quick enough, so you will almost certainly boot from microSD if you “reboot” when microSD is mounted.

There is a package called ksplice to “hot swap” the kernel in Linux, I don’t trust it, and it doesn’t seem to be available to Debian stretch. but again that’s beyond my knowledge.

Thanks for the reply & explanation. Would be nice to be able to extend the timeout setting. But, I like the reboot hot uSD trick. Gonna try it on the SanDisk uSD, just for laughs.