After messing with eMMC partitions, PBP won't boot, even from SD card

[manawyrm]

Code:

dd if=kali-linux-2020.2.x.x.x of=/dev/mmcblk2

sounds very good, that's the right command.

Just make sure you've unpacked the image before doing that. (you need an .img file, not .img.xz!) 
If it's still an .xz image, run

Code:

xz -d kali-linux-2020-x-x.img.xz

to extract it. 
Don't run these commands with offsets (like seek=32768) until you know what they're for.