Reboot would be high order blasphemy.
Over the years most, if not all, of the cast had expressed interest in doing more Firefly. I remember Nathan saying like 15 years ago when the lottery was at like a billion that he was playing and if he won he was going to put a huge chunk of the money to bringing it back. Unfortunately he didn't win.
It's probably too late to get the cast back together now too. It's 20 years later and even Summer is in her 40s now. Glass passed in 2016 which you can get around by having it post Serenity but then you lose Wash too.
The biggest issue though is Joss being persona non grata now. I would not want the show back without him at the helm. He'd have to have some sort of real life redemption arc for me to even toy with bringing the show back.