I've compiled the fastboot from
https://github.com/yifanlu/Fastboot-Kindle
and got it working
ran the rp ify on the mmcblk0p2 mount and was successfull
fastboot flashed the main kernel diags_kernel the diag partition
rebooted into diag mode and went straight into login prompt and the root password blank or mario do no work.
logged in with framework and password mario.
It seems that /etc/shadow was not modified and cannot find dropbear anywhere on the filesystem.
I think that the diags partition is not being written.
It seems that fastboot flash diags mmcblk0p2 is over too fast. filesize is about 65MB and it is finished running after about 4-5seconds