After up BIOS - long power on USB-CD bios recovery downgrade Toshiba z30-a

Toshiba Portege z30-a PT241U-0ER012
https://support.dynabook.com/support/mod…8H&osId=3333785
Problem: after updated the BIOS - laptop a long power on.

I downloaded the BIOS file from the official website Toshiba and decrypted it.
And got a file size of about 3.67MB, ie it’s just the BIOS region. Attach file out4.0.zip.
I opened this file with PhoenixTool 2.73. He smashed it into modules.
I am interested in the contents of the module 3D17205B-4C49-47E2-8157-864CD3D80DBD_1777.ROM.
Opened in the hex editor, at the bottom there is interesting information:



EL TORITO modern BIOSes are looking for the boot sector on CD-ROM in the ISO 9660 standard?
To recovery the BIOS on my laptop, do I need to rename the file I decrypted to "fvmain.fv" and burn it to a CD-ROM in ISO 9660? This laptop does not have cd/dvd-rom device.
Is it possible to do this with a usualy USB flash drive with FS FATA32 and press a hot key combination to restore to version 4.0? What a hot key combination?

The USB flash drive on the Phison controller can be easily converted/firmware to USB-CD mode. The instruction is available on the website usbdev.ru
Then write the file to USB-CD.
The question is how to prepare the file?

if search in the hex editor(open my dec. file) for the word ".bin" in the format UTF-16, I see that there is a mention of the file ECB7???.BIN - this is the file EC, "???" - this is the version EC in the file name.



Problem: after updated the BIOS - laptop a long power on.
Before to the update:
BIOS 4.0
EС 1.0
After the update:
BIOS 4.3
EС 1.6

I press the power button - the LED indicators and the fan work and the screen is black.
After 5 sec the indicators do not light and the fan does not work. That is, the laptop turned itself off. After 5 seconds, it automatically turns on, the logo Toshiba is displayed on the screen for a long time. then download the OS.
I disassembled the laptop, soldered the bios chip, and the master in my city cleaned the ME - nothing has changed. The master correctly cleaned the ME region.

I thought I needed to flash the multicontroller to version 1.0, but it is BGA, model IT6511FN. (

Downloaded BIOS version 4.3. Yes, there is a version of BIOS 4.3 and EC 1.6.
Downloaded BIOS version 4.0. Yes, there is BIOS version 4.0, but EC 1.4. Amazingly. Before to the update BIOS, the version EC was 1.0 with BIOS version 4.0.
And version EC 1.0 is available only in BIOS version 1.4.

out4.0.zip (2.2 MB)

BIOS.jpg