[Request] Acer aspire 4935g unlock, or just enable VT

[uncleroxk]

Hi,

I need to unlock my bios for VT.

I have tried the steps here(http://www.jakobheinemann.de/j-bios.html) .
I get to unlock the advance menu, but no VT.
http://imghost.ucoz.org/upload3/20111117115308247.png

Just like this one: http://www.bios-mods.com/forum/Thread-Un...pire-4930G


- Manufacturer: Acer
- Model : Aspire 4935G
- Bios Type : InsydeH20 Rev.3.5
- Bios Version : V1.08
- Bios Link : http://global-download.acer.com/GDFiles/...r&SC=AAP_7

I'll make a small donataion and feedback if everything work out.


Thanks

[Cenxx]

Hi,

i've revived from the dead an old acer 4935g, it came with a core 2 duo T6400 wich does not support intel virtualization technology, but i have upgraded the cpu with a T9900 wich does. The problem is that in bios there is not the option to turn on virtualization and i think it's disabled by default.

The option should be in an hidden "Power" menu, "Advanced CPU Control" submenu, "VT Support" submenu item.

I've tried to figure out myself following the instruction on the archived site:
http://donovan6000.blogspot.de/2013/06/i...-tabs.html

And found the texts inside the bios, also fount in the structure an item called "VTd" (but the mainboard has a P45 chipset wich should not support VT-d, i could only get VT-x -- EDIT: it's PM45 chipset, it has VTd --) but i'm still stuck at the dissambly part.

There was an identical request in this forum but since there was no feedback on the last posted modded bios the file was removed, you can start with this to see what was done:
https://www.bios-mods.com/forum/Thread-d...os-Request

Bios file is here:
http://global-download.acer.com/GDFiles/...r&SC=AAP_7

Could anyone help to unlock this bios, or just enable by default the virtualization option?

[Cenxx]

Looks like the disassembly of this bios was not as straightforward as the example i was following, i cound't still find the jumps that skips the missing menu.

So, would it work if i swap all the addresses i can find of one menu i don't need with the address of one hidden menu?
For example, security has the address 0xD570, i could change all the occurrences with 0xD7C0 (Advanced) or 0xCC80 (Power). What i would expect is that i will se the menu Advanced, or Power, instead of Security. Will it work or there are many other thing to check that it won't work and brick the laptop?

Another way i found to try to enable missing items in the bios is by directly altering the NVRAM by writing the correct values to the correct address of the item you need to change, but at the moment i couldn't find a reliable method to find the address i need. If done wrong, you may recover the situation by resetting the bios if lucky, or brick the notebook. Any help on second this method?

[Cenxx]

I'm trying the NVRAM approach do directly switch the variables and downloaded h2ouve to have a dump. Before altering unknown variables i made a try with something that a could change from the bios menu to see what appens, but there is something i'm missing, the variables found via the donovan extraction tools seems to not match with the variable change i see with h2ouve.

For example, here are some settings from the bios main menu:

0x10BDF Setting: Quick Boot, Variable: 0x73[1] {05 09 73 00 01 7C 02 7D 02}
0x10BE8 Option: Disabled, Value: 0x0 {09 09 30 00 00 00 00 00 00}
0x10BF1 Option: Enabled, Value: 0x1 {09 09 31 00 01 00 01 00 00}
0x10BFA End of Options {10 02}
0x10BFC Setting: Network Boot, Variable: 0x74[1] {05 09 74 00 01 80 02 81 02}
0x10C05 Option: Disabled, Value: 0x0 {09 09 30 00 00 00 00 00 00}
0x10C0E Option: Enabled, Value: 0x1 {09 09 31 00 01 00 01 00 00}
0x10C17 End of Options {10 02}
0x10C19 Setting: F12 Boot Menu, Variable: 0x25B[1] {05 09 5B 02 01 1D 00 1E 00}
0x10C22 Option: Disabled, Value: 0x0 {09 09 30 00 00 00 01 00 00}
0x10C2B Option: Enabled, Value: 0x1 {09 09 31 00 01 00 00 00 00}
0x10C34 End of Options {10 02}
0x10C36 Setting: D2D Recovery, Variable: 0x25A[1] {05 09 5A 02 01 1F 00 20 00}
0x10C3F Option: Disabled, Value: 0x1 {09 09 30 00 01 00 00 00 00}
0x10C48 Option: Enabled, Value: 0x0 {09 09 31 00 00 00 01 00 00}
0x10C51 End of Options {10 02}

If i change the Quick Boot i would expect to see the variable 0x73 change from 0 to 1 in i change from disabled to enabled, but in the dump from h2ouve the change is in a different address, in what it looks to me 0x75:

[014] "?Setup"
GUID: A04A27F4-DF00-4D42-B552-39511302113D
Attributes: 0x7
DataSize: 0x2BC
Data:
[...]
00000070: 00 00 00 00 01 01 00 00 01 00 00 00 00 00 01 00
[...]

If i change "F12 boot menu" from disabled to enabled 0x25D instead 0x25B:

[...]
00000250: 00 00 00 00 00 00 00 00 00 00 00 00 01 01 00 00
[...]

If i change "D2D Recovery" 0x25C instead 0x25A

[...]
00000250: 00 00 00 00 00 00 00 00 00 00 00 00 01 01 00 00
[...]

I can't undestand what i'm doing wrong. Does 0x73[1] neans something different than address 0x73 1 byte in size? Is it an offset since it looks like all the addressed are shifted by 2?

These are the option for VT and VT-d:

0xCFAB Setting: VT Support, Variable: 0x1AF[1] {05 09 AF 01 01 3A 02 3B 02}
0xCFB4 Option: Enabled, Value: 0x1 {09 09 31 00 01 00 04 45 00}
0xCFBD Option: Disabled, Value: 0x0 {09 09 30 00 00 00 05 45 00}
0xCFC6 End of Options {10 02}

0xF049 Setting: VT-d, Variable: 0x1C1[1] {05 09 C1 01 01 48 01 49 01}
0xF052 Option: Disabled, Value: 0x0 {09 09 30 00 00 00 11 00 00}
0xF05B Option: Enabled, Value: 0x1 {09 09 31 00 01 00 10 00 00}

Could i safely change to 1 the variables 0x1B1 and 0x1C3 with h2ouve?

[Cenxx]

Looks like Acer bioses aren't very popular!
At the end, after almost bricking this poor notebook, i managed to change che variables 0x1AF and 0x1C1 to one with h2ouve (if somebody is interested, please ask), but still virtualization in windows is not recognized, can't enable hypervisor, intel processor identification utility says the processor doesn't have virtualizazion technology and vmware player before installation says that there is not a compatible processor.

Next step, find a way to read the model specific register 0x3a to see the value but can't remembre at the moment how i did it. Before applying the changes it was 1, witch means disabled and locked. It it's still 1 maybe the bios ignores the settings, and it means go back to step one, the disassembling... aaargh!

[Cenxx]

Ok, i'm not that smart, what the intel processor identification utility says is that the cpu does not support VT-x with Extended Page Tables, but it has Virtualization Technology. Virtualbox with ubuntu 64 seems to work (at least the installer, installation in progress) and same with vmware player 12 on which i explicitly choose VT-x. Vmware from version 14 does not work since it requires EPT, and core 2 does not support that.

So i can finally says that enabling VT on acer 4935g is possible. It will be possible to change every hidden property for which the variable address is known. The caveat is that if the bios values are reverted to the default values or the cmos cleared, the procedure with h2ouve must be repeated.