Xperia z2 in a boot loop topic

So, i bought an xperia z2 today, updated to 4.4.4. and then decided to downgrade to 4.4.2

NOPE

now i am in a bootloop

additional info:
The phone was probably with a german customisation (it had an si of 1279-4156.3 according to the box) and i flashed a greek customisation... Could this be the problem?

Also, i did NOT UNLOCK my bootloader

Any suggestions will be REALLY appreciated

EDIT: gonna flash a german customisation ftf as soon as i download it... just to see what will happen