Is it a firmware patch or a software update? If i understand things correctly, firmware is software that controls the hardware, while software is the user application. Panasonic seems to use the word Firmware for SD Card patches that address various issues, but they use the word Software for the Viera Cast downloads, like the new Viera Cast interface and the addition of Pandora. If this download were firmware that corrects a particular issue, wouldn't they call it firmware instead of software? I can't remember if it was ever verified that the recent 1.28 Software download corrected THX or not, or if the fix had to come in the form of an SD card patch.
And are you sure about that version number? The Viera Cast download i did last night is version 0190-2010, which translates to 1.29 (not 2.9) if i'm converting it correctly.