I think then that my last statement was correct. I'm short on time at the moment, else I could find a post explaining how to do this. Perhaps you can find one, we've had quite a few of them I suppose.
To summarise though, this is what you'll need to do:
1) make a bootable SD, but not Manjaro. I like to use the Debian Desktop image from the wiki.
2) take the bottom cover off the PBP.
3) switch the eMMC off
4) boot from SD
5) download a bootable eMMC image, preferably just use the same Debian image from step 1.
6) turn the eMMC on
7) "bind" the eMMC
8) install the new image to the eMMC
9) power down
10) reassemble the PBP
To summarise though, this is what you'll need to do:
1) make a bootable SD, but not Manjaro. I like to use the Debian Desktop image from the wiki.
2) take the bottom cover off the PBP.
3) switch the eMMC off
4) boot from SD
5) download a bootable eMMC image, preferably just use the same Debian image from step 1.
6) turn the eMMC on
7) "bind" the eMMC
8) install the new image to the eMMC
9) power down
10) reassemble the PBP
