Funny you both mention shidehack and vh. I am running some old R808 and a few R606 in my shed. It is only thing I use cgminer at moment. I already tried using vh's fork of cgminer and is doing the same.
I believe it is a problem with Raspbery Pi OS 64-bit when it has more than four sticks. I used my RPi with RetroPie installed as it was closest thing. I had no problem with it recognizing all the Antminer U2.
It has been fun messing with these old stick miners. I held on to two of each stick miner I have ever used. But I think I just uncovered what might be a financial headache in the form of paper wallets. I used these to buy used GPUs 8-10 years ago.

I have a RPi 4 running a mix of 10 U1/U2s using VH's fork of CGMiner 4.11.1. The RPi 4 is 4GB version and is updated to the most current Raspbian (Buster).