
A short update was given on the Dev Team blog earlier today:
Today we released an ultrasn0w update that fixes an issue for those running firmware 3.1.2 with the 04.26 baseband. That specific combination resulted in a missing carrier name in the upper left-hand corner of your home screen. Today’s ultrasn0w update from 0.91 to 0.92 fixes that problem (which was an important issue for roaming). You should see the update available if you have http://repo666.ultrasn0w.com as a Cydia source. Enjoy!
According to AIS, the carrier logo has been fixed for the following countries: USA, Thailand, Austria, Trinidad, Germany, China, Kuwait, Serbia, Poland, France, Nigeria, Egypt, Pakistan, Ireland, UK, Turkey, Sweden, Switzerland, Malaysia, Hungary, The Netherlands, Bahamas, Jamaica, India, Israel, Belgium, Canada, Portugal, Denmark, Costa Rica, Italy, Chile and Argentina.