AMD published ucode for new SI (TAHITI, PITCAIRN, VERDE) and TN (ARUBA) hardware here: http://people.freedesktop.org/~agd5f/radeon_ucode/ radeon-ucode needs updating to reflect the additional ucode files. Reproducible: Always
Which exact files are missing from radeon-ucode-20120320? Please reopen if something is not there that should be.