i updated my backtrack 4 R1 finally using the directions mentioned here. However, after the upgrade my Intel Corporation Wireless WiFi Link 5100 wireless adapter stopped working. My first thought was that the driver was corrupted or something after the upgrade.
But looking through the ‘dmesg‘ command output it became clear that during the startup a particular file iwlwifi-5000-2.ucode could not be located. I thought a reinstall will do it (always works right?).
# apt-get install firmware-iwlwifi
No luck yet! Searching for these files showed me that they were in two locations and both of these were identical (verified via md5sum) :
/lib/firmware-2.6.30.9/iwlwifi-5000-2.ucode
/lib/firmware-2.6.34/iwlwifi-5000-2.ucode
So I just added a symbolic link as follows:
ln -s /lib/firmware-2.6.34/iwlwifi-5000-2.ucode /lib/firmware-2.6.35.8/iwlwifi-5000-2.ucode
Voila! It now worked! Hope it helps!