Since I didn't have time to verify this in the existing modem images post for the non-LTE devices, I decided to post here detailing what I know works if you want to daily-drive 5.1.1 nightlies on your T999. The working baseband I've flashed is T999UVENC2 (intended for factory/OTA 4.3 Jellybean), from the thread here highlighting a collection of factory zips as they relate to stock TouchWiz "Nature UI" ROMs. All my flashes have been done though TWRP I loaded through Odin ~v1.85; I believe this configuration with stock kernel and CWM should still work, though TWRP seems as close as we're going to get to brick-proof. The wrong baseband can brick everything, hence my post.
Mods, please delete if you wish, though this seemed important to me considering I might have saved ~$1000 USD upon not buying an unlocked Note Edge or dev edition Xperia when I got it working.
Mods, please delete if you wish, though this seemed important to me considering I might have saved ~$1000 USD upon not buying an unlocked Note Edge or dev edition Xperia when I got it working.