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How to fix Pinebook not booting from eMMC when SD Card is inserted. I finally dodged the bullet and installed the latest version of Armbian with kernel 5.4.2 on my Pinebook eMMC card. Of course, I made this decision after I managed to fix the external WiFi issue that I explained before, here. Everything went fine and smoothly, thanks to the handy armbian-config. This tool is a gem in my opinion because I didn’t need to play around with the notorious dd command to install the Armbian to my eMMC.
Anyhow, everything was fine and great. I then decided to use my 64GB SD card as extra storage to put my data there, given the fact that my Pinebook eMMC only has 16GB capacity. So I formatted my SD card and then moved some of my data there. But then the Pinebook didn’t boot of eMMC when the SD Card was in.
What I did was to take the SD card out and try again. It boots up normally from eMMC, as expected. I then thought with myself that I may not format the SD card. Hence, I first deleted the partition and reformatted it. But it didn’t work.
I searched on the internet and came to this realization that I ought to overwrite the MBR. With a simple search, I found the solution, thanks to martinayotte from Pine64 forum,
https://forum.pine64.org/showthread.php?tid=6819&pid=42411#pid42411
So basically, I had to run dd to zero the MBR.
$ dd if=/dev/zero of=/dev/mmcblk0 bs=1024 seek=8 count=2048
Yeah, I know, dd again. But anyhow, after running the above command, Pinebook managed to boot up from eMMC while the SD card was inserted.
As the last step, I opened Gparted to do my partitioning on the SD card, that is when I realized the partition table has messed up. But no worries, I managed to create a new partition table using Gparted. And after I’ve done with the partitioning, I rebooted the system and worked perfectly.
Hope you enjoyed this article.
