Fix Pinebook not booting of eMMC when SD Card is inserted

Fix Pinebook not booting of eMMC when SD Card is inserted

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,

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.