I have totally debricked my kindle touch after was completely
erased, and i want to thank you guys for the help, especially to eureka for the new cutom u-boot (with fastboot included).
I will write the steps i have followed:
First of all i must say that my kindle was completely erased, kernels, u-boot, partitions.
1. I have attached a serial cable in order to diagnose the problems (i think this can be done also without having a serial).
2. I have tryed to load the custom u-boot(fastboot, main, diags) with MfgConfig tool, and becouse i had attached the serial i was able to see that my idme vars board id and S/N were deleted, and becouse of that u-boot couldn't initialize the RAM in order togo further.
To solve this issue i have downloaded the u-boot source code and modified it in order to set my idme vars back (recovered from a previous log). After i have loaded my custom u-boot with MfgConfig all my idme vars were recovered, and now the problem was that i had no kernels, so the boot process go further.
3. I wanted to flash my kernels back with the fastboot tool but now the problem was that fastboot it's included in u-boot bist that was deleted too on my kindle. So from this point i had no options to flash back my kernels until eureka provided a cutom u-boot with fastboot included (Thank you very much for this, fantastic work
Now with the new custom u-boot i was able to flash back my diag kernel and partition in order to enter the diags menu (after i remaked all partitions from the recovery menu that i was able to access it from the serial console).
After the reflash i was able to get my kindle to the diags menu ( by loading diags with MfgConfig). After this, i have accesed the linux command line window (D.Exit Reboot or Disable Diags -> ..Go to login promt).
After login i have used the linux terminal to reflash my main kernel and partition:
dd if=/mnt/us/mmcblk0p1.img of=/dev/mmcblk0p1 bs=4K
dd if=/mnt/us/kt_5.1.2-kernel_main of=/dev/mmcblk0 bs=4096 seek=65
dd if=/dev/zero of=/dev/mmcblk0p3 bs=4K count=1K
I must say that i haven't used ssh in order to do this (had some problems).
After a little research i have found that /mnt/us it's actually mounted to the windows partition (partition 4 that it's visible on windows after you put your kindle in USB mode in order to copy files). So i have just copyed the image files to the kindle (without using the ssh) and used the dd commands.
Also i had problems to reflash my main kernel with fastboot, so i needed to reflash both (the main kernel and main partition with dd).
After this i was able to start my kindle in main with the MfgConfig tool, but without Mfg, my kindle wasn't able to start alone as it should. (This becouse u-boot probbably was corrupted or deleted too).
4. The last step i have reflashed my u-boot with fastboot (i have used the main u-boot bin provied in MfgTool). After this i have verifyed all my idme vars and they were the same as original, so everything was ok.
After reflashed u-boot i was able to start my kindle from the power button without any help of MfgTool or other tool. After several tests, i can say now my kindle it's as new, and everything it's working as expected.