Easiest fix would be to restore from your NAND since you have bootmii as boot2. If you don't have a nand backup then there's a semi-brick fix HERE. Or a Restore with boot2 with no NAND backup HERE.
I don't think you have a semi brick though. Semi brick is when you accept an out of region update. I'd restore your own nand or use the boot2 method linked above.