Il Mio Problema
I was having intermittent connection issues on SATA 1+2 ports.
La Mia Riparazione
The repair went off without a hitch. I replaced both the superdrive cable and the HDD cable.
Il Mio Consiglio
If you are having random hangs and kernel panics on heavy I/O with this MacBook Pro model (mid 2012), this is the fix if the HDD or SSD are known . . .