Booting CE from SD-card on Odroid-C4 with EMMC inserted

I have a C4 with CE 9.2.3 on emmc installed.
Now I want to boot my C4 from SD-card with a CE-testversion.

Question:
Have I always to open the C4-case, remove the emmc, insert the SD-card and reboot?
Or can I leave the emmc inserted, insert the SD-card and boot from SD-card?
At the moment if both emmc and SD-card are inserted, C4 boots always from emmc.

I thought it had priority. I think I changed priority originally on the N2 but it lead to some confusion with other distro’s. HK wants it this way although I think it’s more logical that SD has the priority.

If you have a CE image on eMMC it will load the bootloader from eMMC. This can’t be avoided as the SoC have this priority burned in and can’t be changed. When bootloader is loaded then it looks first on uSD to boot and then eMMC. So Linux will be booted from uSD when insert.
So to do this it is recommended to have a image on both media almost the same status. But the bootloader does not change that often so it’s ok to have 9.2.3 on eMMC and a nightly on uSD.

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yes, you are right, it works as described.
thx!

A couple of videos have appeared on Youtube from user Dongjin Kim that demonstrates how to set-up multiboot on the C4.

[ODROID-C4] Multiboot - Part#1](https://youtu.be/v4DdxJv74fU)
[ODROID-C4] Multiboot - Part #2](https://youtu.be/KGmx05-DXrg)

These two examples deal with booting CoreELEC from the SD card and Android from the eMMC but I would imagine that it would be relatively easy to work out how to boot different versions of CE from each media using the same methodology.

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That’s good. @tobetter needs more subscribers so let’s all hit the subscribe button.

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Hi,

Yesterday I bought an Odroid C4 with emmc 16gb Android, with the idea of ​​using it with CoreElec on the sd card, or vice versa ( CE on emmc, Android on sd ). I installed the latest versions of Android PIE 64bit(20201221) -> emmc and CE 9.2.5 -> sdcard and petitboot from here http://ppa.linuxfactory.or.kr/images/petitboot/odroidc4 - ODROIDBIOS-20201028.tar.gz. -> Android/emmc.

Petitboot installs without errors, finds devices at startup, CoreElec starts well, but Android only starts in the recovery menu.

If anyone managed to dualboot Android / Coreelec, please let me know what versions (android and petitboot ) they used. The Android and petitboot I used are recent and there may be some problems for now, but I’m not sure if I didn’t do something wrong.

Thanks.

Post your questions regarding PetitBoot here