How to change to beta?

I’ve got two Herelink TX’s, an older V1.0 running the latest Beta and a V1.1 running stable. The new 1.1 unit has all kinds of issues. The problem happens when connecting to a V1.0 airuint or the V1.1 airunit. The V1.1 TX is sitting around 15 to 20c higher than the old Herelink. My packets from the hotspot on my laptop drop down to 20 or 30%. The hotspot drops out and best of all, It just shuts down for no apparent reason. So really the only difference between the two is the firmware and a brighter screen. For the life of me I can’t get the new Herelink on the Beta channel. First off it’s hard to get it into fastboot. Pressing the power and D buttn yeilds 90% of the time it shuts down so you can’t even power it back up. So when plugging it back into the USB, no icon of charge state indicator. Leave it on the chager and it comes back so you can repeat the futile sequence again. When I have got it into fastboot, I downloaded the flasher_win with beta tacked on after the space. It flashed and then boots, but forces an OTA update at the start screen…So I had beta, but no more lol. Updated the OTA app as suggested, but again there’s no beta button to select in the system update screen. How can getting on the Beta channel be so hard?