I also tried rolling back the kernel to a previous one using another method from XDA and rooting that way, but flashing the kernel bricked the device and I had to reflash in flashmode back to stock. Here are some details re the build number I'm on and everything. I don't see anybody else who has had this particular problem with this device. Is there a way to flash a firmware that has root already?
Andoid Version 4.1.2
Baseband version 9x15A-ACEFWMAZQ-30110041-32
Build Number 10.1.1.A.1.319
Asking for help here is always a last resort - just picked up the Xperia Z on Bell the other day as a straight-up trade for my Galaxy SIII as I was starting to get a little bored with the S3 and wanted a new phone to play with. Little did I know that this would be project it has turned into just trying to get this thing rooted, let alone flashing any custom ROM. Every time I try to root this thing, I get absolutely nowhere. I have tried the easyroot toolkit about a hundred times and it shows that it was rooted successfully but when I reboot, no luck. I tried the other rooting method where you follow the command prompts and enter service mode - select display test and wait for the screen to go white but that's as far as it goes, it just sits there with a white screen. Another guy said to try turning the display off then back on a few times to see if that kicked it into gear, but nothing, that's as far as it gets.