Can't program rock pi s0 emmc

So I tried following the documentation for the s0…
But it doesn’t mention which bootloader to use for RKDevTool. After searching these forum I think i found the correct one being this, but not sure.
Atleast with that i get past the initial steps but now I’m stuck at ‘Start to switch storage’, no matter which option i choose, it either fails or crashes…
Any ideas?