Happy eMMC and SDcard OS usage for Pinebook Pro Newbies...

[Mangled]

OK, lsblk 1st,, boot0 and boot1 are on emmc, I will use terms /dev/SD and /dev/emmc,,
replace SD and emmc with right mmcblkX
Then, sudo gdisk /dev/SD,,, the screen that comes up will have this section

Partition table scan:
  MBR: MBR only
  BSD: not present
  APM: not present
  GPT: not present

So you can tell the partitioning style of the disk, Ayufan often uses GPT
If it is mbr, you save 1 sector, if gpt save 34 sectors,,, (dd default bs is 512 Bytes, 1 sector)
(GPT has protective mbr, 1 sector, GPT boot code, 1 sector, partition table, 32 sectors,,4/sector,128 partitions)
make a directory to work in, empty
cd ; mkdir uboot-sav ; cd uboot-sav
save SD mbr
dd if=/dev/SD of=SD.ubuntu.mbr count=(either 1 OR 34)
save ubuntu uboot(optional), good practice to always be able to go back
dd if=/dev/SD of=ubuntu.uboot.16M bs=1M count=16
Transfer 1st-16M emmc->SD
dd if=/dev/emmc of=/dev/SD bs=1M count=16
restore mbr
dd if=SD.ubuntu.mbr of=/dev/SD  (count not necessary, will stop at end of file)
Also a good practice to give self documenting names, very helpful a month later
This assumes manjaro on emmc,, ayufan ubuntu on SD,, ubuntu boots OK
Doesn't matter where you boot from, but if SD card is in, will boot ubuntu
Then test, remove/disable emmc, can SD boot OK?  If so, transfer ubuntu to emmc,,
with rsync (already in forum OR on other computer OR do an install from image,, BUT
BEFORE rebooting transfer manjaro uboot to emmc (saving emmc mbr 1st, and restoring last)

Thank you so much. Yep the image had GPT partition. Followed your steps and it worked. I booted into Ubuntu 20.04. However I updated Ubuntu to 20.10 and it boots but fails and tells me to enter maintenance. I may have to attempt the steps again for the new update.