Bluetooth Not Working After Flashing

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Hello i recently flashed AOPK 4.4.2 and bluetooth wont turn on.
My phones state
UBL
AOPK 4.4.2
AOPK boot.img kernel (form the rom zip)
Rooted

My question
what causes those problems like wifi , bluetooth and network not working on phone after flashing a rom
is it the kernel the rom itself or the clearing of previous rom data going wrong ?

Thank you :D