Unbrick a PW3 (Fastboot)

Hello,
iam new in this Forum and need help by unbrick a PW3 (2015).

I got a PW3 (G090 G1) and tryed to Jailbreak it. I failed :(

I used the Dummies Tutorial (Serial Port) and get a Rapair Screen after erasing the root password. Unfortunatly i erase the MMC while playing around get it back to life.

I read about the fastboot and flashing the kernel, system and diags. So i get the Kindle in the fastboot mode and install the driver on my Windows PC. Fastboot is working and i also can read the serial nr over fastboot.

So far so good, but i cant get the images out of the update_kindle_5.6.1.1.bin.
(5.6.1.1 ist the SW version that was installed on the PW3)
I used the kindletool to extract the .bin but failed at unpack the fwo_rootfs.img to create the images for flasing.

Can someone help me creating the images by a step by step tut or a link where i can get this images?

Sorry for my bad english.

Regards Max