Can you Share the firmware im in the same situation, i bought 5 and all came in good condition, some with trasportation marks, but working ok,
the thing its that i have one in the poolin pool fixed firmware. im with socs firmware too

no matter what always come back to the user in the same account of ldt3p. at stratum+tls://btc-bj3.ss.poolin.com:5222