Edit: B&N has since posted the update zip on their website. For users with non-US firmwares, I recommend flashing US 1.2.1 firmware (see https://sites.google.com/site/xcdguides/nook/nookB&N). You cannot register 1.2.1 but you can update it before registering. At the "welcome" screen connect the device to your PC and transfer the update zip from B&N. Let the device sleep and it will do the update. Then you can register if you desire.
I can't claim to have done a thorough shakedown but there is no obvious change in the device on FW 1.2.2. I suspect this is a security update to keep the devices in line with new security measures on B&N servers so that owners can still spend money at B&N via the devices But I was curious to see if the cacerts.bks file had been changed since some certificates have already failed (a few of which have been fixed already by @tshoulihane to keep the Kindle app working). No joy there--not that I was surprised. B&N doesn't need cacerts to ensure correct negotiation with their servers via their own apps. Everything seems exactly the same.
To update or not to update
If, like me, you rooted your device earlier with NookManager, the update will fail and your device will spontaneously reboot. This behavior (occurring every Sunday morning as I listened to NPR on the TuneIn app) is what lead me to the conclusion that it was the update process. If you don't give a hoot about the update but you're not keen on having your device reboot on a whim, here is a fix: https://forum.xda-developers.com/sho...59&postcount=3
I don't know about other rooting methods potentially interfering with the update process.
If you just must have the update, it is likely you will need to restore your device to stock, re-register it, and leave WiFi on for a week or so until the update occurs (I left mine on the Library screen so I would know when a reboot--taking you to Home--occurred).
Can I root it?
The short answer is "yes".
NookManager is versatile and wonderful, but it does have a bit of dust on it by now. I plan to look into that and start another thread. For now, there are two files which need to be edited in order to use it successfully with FW 1.2.2. You'll want Notepad++ or similar.
Prepare the NookManager card as described in its thread. Examine the prepared card in your PC. You'll see one partition:
In that partition find the folder "scripts". You need to edit these two files:
In both files the change is the same. Near the top of the file you will find this line:
if [ "$SYSTEM" != "1.2.0" -a "$SYSTEM" != "1.2.1" ]; then
if [ "$SYSTEM" != "1.2.0" -a "$SYSTEM" != "1.2.1" -a "$SYSTEM" != "1.2.2" ]; then
Now....there is an issue with a few apps like Opera Mobile and Tasker not wanting to install. They are the only two I have encountered so far. Here is the "fix": https://forum.xda-developers.com/sho...02&postcount=5