Alright, update:
I've reflashed, and reconfigured, and now I can connect via microusb, but whenever it sleeps, it gargles the connection and doesn't come back. I get this:
Final-sleep: 30s; RT: 2456
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"|▒▒▒r▒bl▒c▒p~▒N▒$on▒▒#bp▒▒bd`r$▒{▒▒nocp
And then it doesn't come back until I...