You could always make a backup of your Manjaro SD, burn the emmc-installer image to it, restore the backup to the SD, boot from emmc then insert the SD, and copy over all your user files from the new install. If you've added packages, you'd probably need to go through and reinstall those.
There's another way I had to figure out years ago on the PB1080, I'll see if I can dig it up. Nevermind, I found it, but it concerned not having enough space on an SD to decompress an image to dd.
To safely copy your install, you'll want to boot into another Linux SD install, use an adapter to mount your current SD install, and then dd that over to the emmc. You don't want to do it from within your current install. There's a huge risk of data loss/corruption.
There's another way I had to figure out years ago on the PB1080, I'll see if I can dig it up. Nevermind, I found it, but it concerned not having enough space on an SD to decompress an image to dd.
To safely copy your install, you'll want to boot into another Linux SD install, use an adapter to mount your current SD install, and then dd that over to the emmc. You don't want to do it from within your current install. There's a huge risk of data loss/corruption.