Need help: How do I flash EC.ROM?

[gens]

I'm new to BIOS world, so sorry if I am asking something really trivial.

I'm trying to downgrade my Toshiba Satellite C55-B5202's BIOS from version 5.10 (latest) to 1.70. Since Toshiba's BIOS flash utility doesn't allow downgrading BIOS, I downloaded BIOS flashing utility from AMI website. Also I extracted the following files from Toshiba's .exe file.

  BIOS.ROM (size: 8MB)
  EC.ROM (size: 128KB)

Using AMI's afuwin utility, I was able to flash BIOS.ROM. Not knowing what to do with EC.ROM, I rebooted the computer. I was able to enter BIOS and confirmed that BIOS was indeed downgraded to 1.70 successfully. However, I noticed that EC version still says 5.10 as below.

  System BIOS Verion: 1.70
  EC Version: 5.10

I tried to install Windows 10 anyway, but the installer didn't recognize my hard drive.

So, I created a bootable USB stick with afudos.exe on it and tried to flash EC.ROM part. It tried using /E and /EC options without success. However, I could flash version 5.10 BIOS.ROM using the following command and bring the computer back to the initial state.

  afudos.exe BIOS.ROM /p /b /n /k

So, the computer is not bricked, but my goal is not accomplished. I need to flash version 1.70 EC.ROM on this computer somehow.

I did lots of search in this forum and internet but the only information I could find wat that EC.ROM has to do with Embedded Controller. No one seemed to know how to flash it.

Any help would be appreciated.

[gens]

Okay, I made some progress. I still don't know how to flash EC.ROM, but now I can install Windows and use it. Here is what I was dong wrong, I think.

When I flashed version 1.70 using afuwin, I used a GUI version and left all options as default. That means I updated only Main Block (which corresponds to /P option) but not Boot Block, NVRAM, etc. So, I used my USB stick again and used exactly the same afudos.exe command as I mentioned in my previous post, but with BIOS.ROM I extracted from Toshiba's BIOS version 1.70 program, and now the problem is gone.

Now, the mystery is the role of EC.ROM. Since it came with Toshiba's BIOS update program, it must have some role.. If anyone has insight, please let me know.

[gens]

Here are error messages I get when I run afudos.exe.

afudos.exe bios.rom /p /b /n /k /e
c6 - Error: No EC blocks found in system ROM.

afudos.exe ec.rom /p /b /n /k /e
3 - Error: ROM file size does not match existing BIOS size.

afudos.exe ec.rom /e
3 - Error: ROM file size does not match existing BIOS size.

afudos.exe ec.rom /ec
ac - Error: Invalid EC Header Table.

I'm guessing that there is a way to merge BIOS.ROM and EC.ROM.
Anyone?

[vcolaon]

main bios is main flash chip and ec rom is a separate flash chip located near cd rom connector. on c660 is named U22. look for it in sthe schematic

[poply]

Here are error messages I get when I run afudos.exe.

afudos.exe bios.rom /p /b /n /k /e
c6 - Error: No EC blocks found in system ROM.

afudos.exe ec.rom /p /b /n /k /e
3 - Error: ROM file size does not match existing BIOS size.

afudos.exe ec.rom /e
3 - Error: ROM file size does not match existing BIOS size.

afudos.exe ec.rom /ec
ac - Error: Invalid EC Header Table.

I'm guessing that there is a way to merge BIOS.ROM and EC.ROM.
Anyone?

Sorry for replying on such an old thread, and probably you aren't even searching on how to solve this anymore BUT

I had to stop by and say THANKS! I was supposed to fix and upgrade my wife friend's laptop but instead messed it up by installing latest BIOS version (which for some reason was under that laptop drivers and updates page). I installed 5.1 just like you, WLAN and LAN caused system to freeze which is why I went on searching how to overwrite an older version and install 1.7. After I've done that I came to the exact same issue where my SSD was not being recognized anymore and luckily, I found your post here, created DOS bootable USB via rufus and managed to install bios properly and had no issues after that. My EC still says 5.1 just like yours but I wasn't able to find a way on how to flash it either but I hope it won't cause any trouble anyway.

Thanks again!

Best regards,
Poply

[HectorZanardo2]

Here are error messages I get when I run afudos.exe.

afudos.exe bios.rom /p /b /n /k /e
c6 - Error: No EC blocks found in system ROM.

afudos.exe ec.rom /p /b /n /k /e
3 - Error: ROM file size does not match existing BIOS size.

afudos.exe ec.rom /e
3 - Error: ROM file size does not match existing BIOS size.

afudos.exe ec.rom /ec
ac - Error: Invalid EC Header Table.

I'm guessing that there is a way to merge BIOS.ROM and EC.ROM.
Anyone?

Sorry for replying on such an old thread, and probably you aren't even searching on how to solve this anymore BUT

I had to stop by and say THANKS! I was supposed to fix and upgrade my wife friend's laptop but instead messed it up by installing latest BIOS version (which for some reason was under that laptop drivers and updates page). I installed 5.1 just like you, WLAN and LAN caused system to freeze which is why I went on searching how to overwrite an older version and install 1.7. After I've done that I came to the exact same issue where my SSD was not being recognized anymore and luckily, I found your post here, created DOS bootable USB via rufus and managed to install bios properly and had no issues after that. My EC still says 5.1 just like yours but I wasn't able to find a way on how to flash it either but I hope it won't cause any trouble anyway.

Thanks again!

Best regards,
Poply

I have exactly the same problem!
In my case I did Downgrade, but I installed a smaller version that now doesn't recognize any devices.
I wonder just how they did to extract the .rom file from this Toshiba installer. I'll do the same process you did. Can you help me
My model is C55T-B5110