Pinebook Pro won´t boot either from eMMC or microSD
When you try to boot from emmc (no sd inserted) do you get any leds?
When you have no leds (except for red charge led, on side) it may be "hard locked"
OR no uboot may be findable, not likely here
You can try, not likely to solve, press and HOLD pwr button, 20-25 seconds
(with no "bad uboots connected, ie no SD card, or emmc disabled, wherever bad uboot is)
--edit--
Someone on the manjaro forum had to switch arch dtb/ use manjaro dtb to make arch install work
When you have no leds (except for red charge led, on side) it may be "hard locked"
OR no uboot may be findable, not likely here
You can try, not likely to solve, press and HOLD pwr button, 20-25 seconds
(with no "bad uboots connected, ie no SD card, or emmc disabled, wherever bad uboot is)
--edit--
Someone on the manjaro forum had to switch arch dtb/ use manjaro dtb to make arch install work