I tried upgrading my Z120BT with original firmware to the CNSD 210-FM firmware. Obtained rar file, extracted SD1 to root of my SD card and inserted card. It asked me if I wanted to start upgrade which I did, then said "Incorrect SD Card. Please insert correct one". I can't seem to get it out of this rebooting without SD card says "no SD available. Insert SD to continue".

Have I bricked my unit.

you have not bricked your unit.

to reset upgrade progress (i.e., to restart upgrade from 0%):

http://avic411.com/index.php?/topic/35109-avic-f10bt-99-installed-wrong-sd-card-insert-right-sd/#entry258184

to kick it out of upgrade mode completely:

http://avic411.com/index.php?/topic/35109-avic-f10bt-99-installed-wrong-sd-card-insert-right-sd/#entry258286

dont use CNSD-210FM - go straight to CNSD-310FM/UC - read the thread