Tried to install on Hyper-V - does not even go to the installer from ISO image. Starts, hangs when it says "Ready" but nothing more happens. 3 steps backward from v5 - on a kernel that SHOULD support Hyper-V (though I suspect that is a lot more the old ISOLINUX version - I suspect taht the new kernel is not even booting at this stage).

will i by upgrading to v6 beta solve my driver problem?
as posted on thread below:
http://forum.mikrotik.com/viewtopic.php?f=2&t=56919

also, is it gonna safe to downgrade to v5 later?

will i by upgrading to v6 beta solve my driver problem?
as posted on thread below:
http://forum.mikrotik.com/viewtopic.php?f=2&t=56919

also, is it gonna safe to downgrade to v5 later?

yes, no.
if you think newer kernel had attansic NIC driver within(which i can't say about. ask Linux kernel forums/gooru) - its may help.
yes its safer (for hardware and config and ROS itself) to downgrade, but if upgrade to ROS6.xx resolve problem(by newer driver in newer kernel), downgrade similarly - return it problem.
so downgrading make sense Only if you plan to switch to NIC, supported by ROS 5.xx.
but again i think in both cases make sense to change NIC to something different. even cheaper realtek, or atheros -branded NIC or intel(among supported(by ROS) models from them) - would work Way better. just saying.
good luck, anyway.

Do you realize that the post you responded to was 4 years old?