Bitcoin miners and other related stocks have dropped in Friday premarket trading along with bitcoin (BTC-USD), as equity markets appear poised for a weak open.The world's largest cryptocurrency by market cap has dipped 8.9% in the last 24 hours, skidding down to $21.4K, its lowest level since July 27.That, of course, is dragging down the usual names. Hut 8 Mining (NASDAQ:HUT) has slid 16%, Marathon Digital (NASDAQ:MARA) -12.3%, Riot Blockchain (NASDAQ:RIOT), -11%, MicroStrategy (NASDAQ:MSTR) -10%, Bitfarms (NASDAQ:BITF), -7.6%, Coinbase Global (NASDAQ:COIN), -8.8%, CleanSpark (NASDAQ:CLSK), -6.6%, and Bit Digital (NASDAQ:BTBT) -6.3%.Most other tokens have also taken marked legs down. Ether (ETH-USD) -8.0%, Binance coin (BNB-USD) -8.7%, XRP (XRP-USD) -11%, and cardano (ADA-USD) -14%.