[Asus Transformer TF700] georgecoat:
For everybody with similar problem I am posting here how I fixed it.

I tried to push Power and Volume Down together or Power button only it does not react to anything, keeps restarting into TWRP splash screen and rebooting. When TF201 boots, skips fastboot and goes directly into TWRP but never loads TWRP and restarts or hang in TWRP splash screen.

In TWRP splash screen I do not have access to fastboot or do any adb.

I can still get it into APX and I have also created my nvflash backups long time ago and I have them available.

I was ready to start brick fix from the beggining.

But before I would get into that I tried last thing:

First I downloaded file djibe Transformer Prime pack v2 : http://bit.ly/djibeTransformerPrimev2

(contains Windows Universal Naked drivers + android_winusb if step 6 is difficult + Asus UnLock_Device_App_V6.apk + fastboot.exe + adb.exe + nvflash.exe + HairyBean Bootloader and various recoveries necessary + SuperSU 2.82).

Unzip the file on Windows desktop.

What i did first was that I had to restart Windows 10 64 bit into "Disable Driver control" othervise the driver would not install

Windows 8/10 :

On keyboard, type combo : "Windows key + R"

In the command prompt, type :

shutdown -o -r -t 0

It opens Windows Recovery menu:

Go to Troubleshoot -> Advanced Options -> Startup settings -> Restart.

At reboot, hit 7 (Disable driver control) and follow instructions for Windows Vista/7.

Installed driver in extracted directory of "djibe Transformer Prime pack v2" pack (android_apxusb.inf).

Once driver installation is completed, reboot PC as usual.

Then I put all necessary files into nvflash folder.

Get ASUS into APX mode (Power and Volume Up, it will restart, hold it until creen is black)

I realised that old exe files are 32 bit, I had to use new nvflash exe files (from the package djibe Transformer Prime TF201 v2.zip) and replace rest with the files I had stored previously when I did blob backups. So everything I used was original folder but exe files replaced with 64-bit versions from the djibe Transformer Prime TF201 v2.zip package. In the last step I used original ASUS firmware downloaded long time go (also in the folder from the time of my blobs creation). This could be still found on ASUS page or here in the forum.

I started cmd window in nvflash folder and run this:

[B]wheelie --blob blob.bin[/B]

Wheelie 0.1 - Preflight for nvflash.

Copyright (c) 2011-2012 androidroot.mobi

========================================

Waiting for device in APX mode...

[=] Chip UID: 0x15d0787bc3ffa13

[=] RCM Version: 0x30001

[=] CPU Model: Tegra 3

[+] Sending bootloader...

Sending file: 100 %

[!] Done - your device should now be ready for nvflash

[B]nvflash -r --download 5 twrp.blob[/B]

Nvflash v1.13.87205 started

[resume mode]

sending file: twrp.blob

/ 8124520/8124520 bytes sent

twrp.blob sent successfully

After that I was able to get into fastboot finally!

From there I did:

[B]fastboot -i 0x0b05 flash recovery twrp_tf201t.blob[/B]

sending 'recovery' (7934 KB)...

OKAY [ 2.110s]

writing 'recovery'...

OKAY [ 2.128s]

finished. total time: 4.238s

[B]fastboot -i 0x0b05 reboot-bootloader[/B]

rebooting into bootloader...

FAILED (command write failed (Unknown error))

finished. total time: 0.643s

Still no working...

I had to do this:

[B]fastboot erase system
fastboot erase recovery
fastboot erase userdata
fastboot erase boot
fastboot erase misc
fastboot erase cache[/B]

[B]fastboot -i 0x0B05 flash system L:blob[/B]

(this was my path - your's may vary depending where you stored your blob)

[B]fastboot -i 0x0B05 reboot[/B]

Then I started the whole process of flashing the Hairybean bootloader (reboot), then TWRP (reboot) and then the rom 35, gapps, supersu again and I am back to normal.

Thanks : Timduru, matthill.eu, Kang for updated TWRP, TWRP team, Android Root Team, Lineage OS team, TacoNikky, Saber, berndblb, Nektopoli, djibe and Buster!