Upgrading WiFi in a Lenovo T61 ThinkPad to a Windows 8.1 Compatible card via USB Drive

The stock WiFi card (an Intel 4965 AGN) on my ThinkPad crashes every 30 minutes under Windows 8.1 (netwlv64.sys every time).

It also seems not to like the 5Ghz channel (from an Asus RT-N66U) though this was true under Win 7. So I upgraded to an Intel 7260 which is performing flawlessly.

BEFORE Changing the WiFi card

1. Download the Middleton BIOS iso.
2. Download rufus from pendrivelinux.com
3. Follow the instructions at pendrivelinux to format the usb drive as a bootable DOS disk.
4. Copy the files from the Middleton BIOS iso to the usb drive. (either mount it or use 7-zip to extract the iso contents).
5. Make sure your battery is near fully charged (battery icon is green not yellow on thinkpad indicator).
6. Disable the TPM chip in the bios.
7. Suspend BitLocker if it's on.
8. Boot from the USB drive.
9. Run the flash utility (lcreflsh.bat).
10. Wait for several minutes.

Changing the WiFi card

1. Follow the instructions here for removing the wifi card.
2. Insert your replacement wifi card.

TPM can then be re-enabled and bitlocker resumed after rebooting.