If anyone has a 2012 Altima Coupe or Sedan with the Bose non-navigation audio and has ever had their XM radio get stuck on Loading, there is a software fix for it that was released a few weeks ago. I got the update earlier today and it looks like it fixed the problem. I used to have the radio get stuck on Loading at least once per week when changing channels. It would get stuck on Loading and basically crash - I wouldn't hear any XM audio unless I shut down the car and restarted it or if I rebooted the headunit (put it into diagnostics mode then exited diagnostics mode).

This is a free fix under warranty under Nissan TSB NTB12-059. Here is pertinent information from the TSB for reference:

APPLIED VEHICLES:
2012 Altima Coupe built after 1N4(*)L2E(**)CC 115856 // June 20, 2011
2012 Altima Sedan built after 1N4(*)L2A(**)CC 115773 // June 20, 2011
2012 Quest: All
2012 Rogue: All

IF YOU CONFIRM
The customer states that while tuned to an XM® satellite radio channel:
• “Loading” displays on the screen while driving in a clear signal area, with no overhead obstructions.
AND
• No sound is output from the speakers.

The customer may also note the following:
• All other audio sources (AM/FM/CD/AUX) work properly.
• The “Loading” message goes away and sound returns when the ignition is cycled OFF and back ON.
NOTE: This incident, if it should occur, may be intermittent.

ACTION
Install the software update per the Service Procedure in this bulletin.

The dealership puts an update CD in the headunit and lets it run. It only takes about 20 minutes.

Do you know if they have this fix for downloading to a usb drive to update myself?

No you had to go to the dealer for it, they download the software with a special CD.