Tracing EARN & EARP outputs from Iota.  On L1 they go to vias at (2422,518) and
(2449,518).  On L2 they go to vias at (2455,322) and (2492,323).  Tracing made
difficult by flaws in steve-m's grind-down process, but they appear to go to L4,
where they then seem to go to other vias at (491,1254) and (490,1292).  Found
them on L7: going to immediately adjacent micro-vias at (514,1255) and
(514,1295).  On L8 they go to the earpiece speaker.

Tracing the loudspeaker signal path starting with the physical speaker connector
on L1.  The connector part center is about (1930,212).  The connector footprint
on L1 is damaged by steve-m's grind-down process (almost gone), but there seem
to be micro-vias at (1756,251) and (2005,237).  On L2 they go to (1788,231) and
(2021,264).  On L7 they go to micro-vias at (1784,262) and (1992,252).  On L8
they go by some caps and then back to new micro-vias!  The latter are at
(1902,220) and (1903,259).  On L7 the grind-down damage gets in the way again,
but they appear to go to vias at (1935,218) and (1934,260).  Found them on L3:
going to new vias at (3703,311) and (3739,313).  (It might actually be L4.)
Found them on L7: fat traces to micro-vias at (3870,934) and (3898,869).
Finally on L8 they go to the Winbond chip!  The speaker connection pins appear
to be the two leftmost ones in the top row of 9 pins.