They ,RH, locked down 6 equities, I posted the names in #160. By locked down I mean you can sell the the equities but not purchase. They did a similar move to the options.
You can still buy and sell at other brokers. I made a small buy of GME during the flash crash this morning and sold the rebound, quick $120 a share, in my Fidelity account. Some Redditors think the crash was used to unwind the worst shorts. I don't pretend to know.
ETA: I'm watching an interview with someone, JJ Kinahan, from Ameritrade who is talking about their restrictions. Sounds like margins are reduced and you can't sell naked calls.