XTU is ONLY supported on X and K processors.
You have an H processor.
And, you are in the wrong forum.
It was working fine few days ago (so i guess its supported) and saw other guys on youtube undervolt fine with same rigs, don't think its my laptops spec problem
No, it is not supported. Look in this link, under "This download is valid for the product(s) listed below.":
List does not include laptop cpu's i don't get why but i think it should support
The list includes the processors XTU is supported on - ONLY X and K.
XTU is NOT SUPPORTED on your processor.
For more complete information about compiler optimizations, see our Optimization Notice.