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Bios 1.48 downgrade t420
#1
Hello guys, i need to downgrade my t420 from 1.48 to 1.46 to install olehs mod to support 16 gb of ram at 1333mhz, can someone help me with this, please? Thank you.
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#2
(05-01-2016, 04:52 PM)Trexie Wrote: Hello guys, i need to downgrade my t420 from 1.48 to 1.46 to install olehs mod to support 16 gb of ram at 1333mhz, can someone help me with this, please? Thank you.

So this can be done. I had to do it today on my T420 which, FYI,  is Linux box.

I made a bootable DOS flash drive. In my case a 2GB thumb drive. I used an HP tool from within a Windows 7 VM (VirtualBox). However you can clearly download an image from the Internet if you want.

Using Linux:-

I extracted the content of the BIOS ISO file (83uj28us.iso) from Lenovo containing the 1.46 BIOS and placed the BIOS file:-

83ET76WW/$01C8000.FL1 on the flash drive along with:-

PFLASH.exe and
EFILDR16

both from the same ISO file.

Remove any AUTOEXEC.BAT from the Flash Drive:

Reboot the T420 and make it boot from the Flash Drive.

Run:-

PFLASH /sv /sd $01C8000.FL1

I actually renamed the file to BIOS.WPH but I do not know if that is necessary.
I believe these are the options I used. Basically PFLASH had to be told to ignore the warnings.
Use PFLASH /? to get help.

However, my machine did downgrade from 1.48 to 1.46. It can be done.

The T420 is a Linux box. To extract the ISO I used:-

geteltorito  bios83uj28us.img 83uj28us.iso
fdisk -lu bios83uj28us.img
losetup -o 16384 /dev/loop0 bios83uj27us.img
mount /dev/loop0 /mnt/t1
etc etc.

You can find details of all of this on the Internet.
I think I have the names of the iso files correct. Check yourself.
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#3
Hey.. i need this downgrade on my t420 too... i want to mount a egpu, but i think than this bios version block the adapter EXP GDC. Can you explain more about this method?

thanks.
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#4
(05-01-2016, 04:52 PM)Trexie Wrote: Hello guys, i need to downgrade my t420 from 1.48 to 1.46 to install olehs mod to support 16 gb of ram at 1333mhz, can someone help me with this, please? Thank you.

In fact, you can install 16GB at 1866
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#5
(05-13-2016, 11:34 PM)Mozzer Wrote:
(05-01-2016, 04:52 PM)Trexie Wrote: Hello guys, i need to downgrade my t420 from 1.48 to 1.46 to install olehs mod to support 16 gb of ram at 1333mhz, can someone help me with this, please? Thank you.

So this can be done. I had to do it today on my T420 which, FYI,  is Linux box.

I made a bootable DOS flash drive. In my case a 2GB thumb drive. I used an HP tool from within a Windows 7 VM (VirtualBox). However you can clearly download an image from the Internet if you want.

Using Linux:-

I extracted the content of the BIOS ISO file (83uj28us.iso) from Lenovo containing the 1.46 BIOS and placed the BIOS file:-

83ET76WW/$01C8000.FL1 on the flash drive along with:-

PFLASH.exe and
EFILDR16

both from the same ISO file.

Remove any AUTOEXEC.BAT from the Flash Drive:

Reboot the T420 and make it boot from the Flash Drive.

Run:-

PFLASH /sv /sd $01C8000.FL1

I actually renamed the file to BIOS.WPH but I do not know if that is necessary.
I believe these are the options I used. Basically PFLASH had to be told to ignore the warnings.
Use PFLASH /? to get help.

However, my machine did downgrade from 1.48 to 1.46. It can be done.

The T420 is a Linux box. To extract the ISO I used:-

geteltorito  bios83uj28us.img 83uj28us.iso
fdisk -lu bios83uj28us.img
losetup -o 16384 /dev/loop0 bios83uj27us.img
mount /dev/loop0 /mnt/t1
etc etc.

You can find details of all of this on the Internet.
I think I have the names of the iso files correct. Check yourself.

Hello. Please Please can you Upload the Boot Disk for us? I have a T420 with latest 1.48 Bios. I want to Downgrade to 1.46

thaaaaaank o so much
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#6
Hi,

I have 1.48 bios with white list and unlock ram. Please send priv message.
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#7
(08-26-2016, 01:43 AM)Kami3n147 Wrote: Hi,

I have 1.48 bios with white list and unlock ram. Please send priv message.

Is this bios update still available? I sent you a PM as well.
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