It is a nice little device. Even though the 5GHz issue has been around for 3 years now it looks like it is being actively worked on as of this week:
@anon89577378 I agree that an AP would be better, but running ethernet through the wall would be difficult where I want to place the extender. Basically my garage has just barely enough wifi that my phone is still connected, but it is slow. So I'm unable to quickly download a Plex music playlist, an audiobook, or sometimes even a Google map from my car. That's really all I want to use the extender for.
Here is my experience w/ re220.
Bought a new one, got v3, not supported
Bought a reconditioned one, got v2, yay
seemed to work ok, but now that you mentioned it I think uplink only worked on 2.4GHz, not 5GHz
Bought another reconditioned one, got v1, boo not supported Got a serial connection on v1, ran the initramfs version of v2 firmware, booted ok but 5GHz radio does not show up in Luci.
@Lynx a quick attempt seems to match @jedboy's experience. For a quick test I tried to use the extender in client mode. I was able to connect with 2.4GHz. With 5GHz I could scan for 5GHz networks, but when I tried to connect as a client it would not associate with the station. Which seems to confirm that the problem is transmitting at 5GHz.
Such a pity as these are great pieces of hardware. Cheap and aesthetically pleasing. And with original firmware work pretty well (e.g. circa 80Mbit/s which is more than needed for most normal applications anyway).