Yea that is pretty much what any SD IMG for pbp does. That particular one was geared to recreate that first boot experience, and wipe/install to the emmc. Pretty much all others are live imgs. If you can boot the live version of desktop you want, you can also use that to overwrite your emmc install with a live version of Manjaro.
Tried what again? Booting the emmc installer IMG?
I don't know if a live imgs is what you need, but they can make troubleshooting easier. I'd write the live version of the Manjaro IMG you want into SD and boot that. If it booted, I'd probably try writing that same IMG from a USB (to transfer) to the emmc. If that boots you can just make the changes you want to it. The differences were negligible vs the OEM install.
I seem to be having the same problem, and have ordered the hardware necessary to do a fresh installation, maybe of another OS. The posts at Manjaro's forum seem pretty intimidating and I was unable to find a post about this particular problem.
Is there some way to bypass the graphical signin screen and get to a command line on startup?
-v