1) It's not a 100% standard card and Dell has something custom either in the hardware or firmware that causes it to get funky under linux.
It's known problem that some WiFi and mobile broadband card doesn't work on linux. But what linux distro did you use? Have you tried install optional/closed-source driver (few distro require user to do it manually)?
I tried Debian and Ubuntu 1st figuring that when Debian did not work Ubuntu, although close to it may do something a bit differently. Then I switched to CentOS and still no go. Tried every driver I could find related to the card both open and closed. It's not even that smooth under Windows, after install you have to *power down* not just reboot.
Assuming you tried non-free firmware from Debian, looks like you've tried everything that i would try. I only could you to try this guide (
) which also use Qualcomm Gobi.