eMMC frequently not found by Linux kernel (especially on low battery)

[Arwen]

Now I have noticed that booting Manjaro off eMMC was not reliable, and tracked it to U-Boot. Based on another user's forum post, I used the latest default Debian U-Boot files on my eMMC. That has made booting Manjaro off eMMC quite reliable. Perhaps I need to do the same for my Manjaro SD card.

Thanks for the suggestion! A couple of days ago I did:

Code:

cd /usr/lib/u-boot/pinebook-pro-rk3399/
dd if=idbloader.img of=/dev/mmcblk2 seek=64 conv=notrunc
dd if=u-boot.itb of=/dev/mmcblk2 seek=16384 conv=notrunc

Since then I booted the Debian from eMMC two or three times, with decreasing battery levels, and without any problem. So yes, it does look like a U-Boot issue.

But now again I cannot boot from SD card anymore, which is annoying for at least two reasons:

1. For some reason I think video performance was somewhat better in Manjaro, so being able to use it occasionally would be nice.
   
2. Should something go really wrong with my Debian system I cannot boot a rescue system.
   

Overall I'm quite disappointed with the state of U-Boot support for this device. I have two other ARM systems (RaspberryPi 2 and Cubox-i4) where U-Boot produces display output right from the start. This would probably even allow for a boot menu (which I only tested on yet another ARM, a CB5-311). I'm looking forward to improvements!

For the problem on booting a SD card, you might see about a later version of U-Boot. Early ones did not have additional checks for other devices, before booting their own device.

And yes, I too have joined the "Disappointed in Pinebook Pro's U-Boot state" club. (We hold on-line meetings every week or so, to complain :-).

Ideally I'd like to see U-Boot support a simple device menu. So if it loaded off eMMC, and by default it wanted to boot off any installed SD card, I could force select it back to eMMC. Or visa-versa.

Then, I'd like Grub menu for kernel selection and other details related to Linux.

And last of course, I'd like U-Boot in SPI. But, I am in no hurry for that phase, as recovery is more difficult.