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

[v-man]

Note that if you changed the kernel, and other files in "/boot" to ones in Debian, that can prevent Manjaro from booting.

What I did was replaced the U-Boot binaries on disk with "dd" using the default Debian ones, not the files in "/boot".

Sure, that's also what I did. I had not changed Manjaro on the SD card at all. As I understood it from the docs, U-Boot is loaded from the internal eMMC, if available, and only from the SD card if the eMMC is disabled (or probably also if it does not contain U-Boot). But even U-Boot from the eMMC, if configured appropriately, can boot a kernel from the SD card. mrfixit2001's U-Boot, the one I mentioned in this thread's first post, is doing exactly that. Apparently Debian's U-Boot is not configured to do so.

For some reason I had used an older version of mrfixit2001's branch initially: my link goes to 1.1. Now going back to his U-Boot to have the flexibility of sometimes booting Manjaro from SD card, sometimes Debian from eMMC, I opted for version 2.0. I modified his mrfixit_update.sh:

Code:

diff --git a/pinebook/filesystem/mrfixit_update.sh b/pinebook/filesystem/mrfixit_update.sh
--- a/pinebook/filesystem/mrfixit_update.sh
+++ b/pinebook/filesystem/mrfixit_update.sh
@@ -1,7 +1,7 @@
#!/bin/bash

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
-myver="0.0"
+myver="1.99"
if [ -f /usr/share/myver ]; then
        myver=$(cat /usr/share/myver)
fi
@@ -65,10 +65,10 @@ fi

if [[ $myver < 2.0 ]]; then
        # Leave the current kernel version's modules folder in place so that it can be used as the backup kernel
-      echo "Updating Kernel Modules to 4.4.213..."
-      KER="$(uname -r)"
-      find /lib/modules -mindepth 1 ! -regex '^/lib/modules/'$KER'\(/.*\)?' -delete
-      rm /lib/modules/4.4.213 -r
+#      echo "Updating Kernel Modules to 4.4.213..."
+#      KER="$(uname -r)"
+#      find /lib/modules -mindepth 1 ! -regex '^/lib/modules/'$KER'\(/.*\)?' -delete
+#      rm /lib/modules/4.4.213 -r
        mv $DIR/4.4.213 /lib/modules

        echo "Updating U-Boot..."

Actually it seems like DigiKam in Manjaro is now supporting external MySQL databases! So my main reason for having switched to Debian is gone.
And again Manjaro provides much better video playback support. Even full-hd is now working on Youtube (with Chromium).

Still, this u-boot situation is odd. Maybe I should install the version from Manjaro? The version as shown by pacman is: uboot-pinebookpro 2020.07rc4-1.1

I don't even know if I'll continue to have these eMMC not found issues, with the different u-boot I'm using again. I'll report here as soon as I know more.