The problem is, we don't have a Firehose loader for the Leaf2 (or the Poke5).
There's a whole thread where I was trying to help denisuu with his Leaf2.
https://www.mobileread.com/forums/sh...d.php?t=350352
It may be that your timing with the 5x power is wrong.
(I can never get the hang of silly things that require coordination.)
If you are looking at the (internal) UART you can see more easily what's going on.
Also, I have a utility for the UART to get you to recovery or EDL.
But you need to open it up and you need a 1.8V USB UART adapter.