UPS APC BK500EI not working with RB951Ui-2HnD

Well, I’ve been testing for a while without getting much solutions.
With RB751 it works great, but since i migrated all my mikrotiks to RB951Ui-2HnD it stopped working.

routerOS version tested:
6.33
6.33.2
6.33.3
6.34.3
6.35

And with all of them, it happens that after several reboots (of mikrotik) it loads the driver (I believe) and allows me to set the “usbhid1” as port.

It would be nice to use the package because I’m only interested to know when the power fails.

Regards.

Any idea?

Regards

Another test I did… With hub usb without battery it works, directly to mikrotik it does’nt!
I have 2 mikrotiks RB951Ui-2HnD with same version (6.35) and same firmware and it works with 1 of them 100% of the times (after a lot of reboots or disconnecting and connecting usb), but with mikrotik 2 sometimes works fine and some others not.

Other thing i saw is that in some mikrotiks load more drivers than others, like ohci controller.

It would be great to know why I need to use usb hub to allow this to work when with RB751 never had this issue.

Regards