I have successfully downgraded a Toshiba U405-2826 from Vista to XP. It took about 7 hours of hunting, digging and experimentation to find the right combination of drivers. As it turns out, everything you need can be downloaded from the Toshiba support site and installed with some tweaking. In some cases, the default driver is valid for both XP and Vista, in which case the default install works. For others you need specific versions or (in the case of the Conexant drivers) a specific pair.
One important note: By default the internal disk controller comes set to AHCI mode, and XP requires that it be set to "Compatible" mode. In AHCI mode the XP installer won't be able to see your hard disk. Note also that if you update the BIOS after installing XP, it will be set back to AHCI mode and XP will get into a BSOD boot loop. You must reset the disk controller back to Compatible mode after any BIOS update if you have XP installed.
Here is the list of drivers I installed.
driver_touchpad_synaptics_27121B.exe
driver_modem_conexant_27323A.exe
driver_audio_conexant_27320D.exe
driver_bluetooth_27428A.exe
driver_cardreader_o2_27442A.exe
driver_chipset_intel_27115A.exe
driver_lan_marvell_27175C.exe
driver_wifi_intel_26829A.exe
driver_video_intel_26358B.exe (see note below)
You can download these files from Toshiba as follows:
None of the GM965 video driver sets will install using the UI or Windows' "update driver" mechanism. The way to do it is:
One important note: By default the internal disk controller comes set to AHCI mode, and XP requires that it be set to "Compatible" mode. In AHCI mode the XP installer won't be able to see your hard disk. Note also that if you update the BIOS after installing XP, it will be set back to AHCI mode and XP will get into a BSOD boot loop. You must reset the disk controller back to Compatible mode after any BIOS update if you have XP installed.
Here is the list of drivers I installed.
driver_touchpad_synaptics_27121B.exe
driver_modem_conexant_27323A.exe
driver_audio_conexant_27320D.exe
driver_bluetooth_27428A.exe
driver_cardreader_o2_27442A.exe
driver_chipset_intel_27115A.exe
driver_lan_marvell_27175C.exe
driver_wifi_intel_26829A.exe
driver_video_intel_26358B.exe (see note below)
You can download these files from Toshiba as follows:
- Go to the main Toshiba support page at http://support.toshiba.com
- Click the "Express View" link to open a download window where you can enter the specific filename.
- Enter one of the filenames above to download the specific file.
- Lather, rinse, repeat
None of the GM965 video driver sets will install using the UI or Windows' "update driver" mechanism. The way to do it is:
- unzip the driver driver_video_intel_26358B.exe file into a temporary directory
- launch a DOS command window and cd to that temporary directory
- "force" install the driver with the command "setup -overwrite"
