Regarding overheating: Since class 0 AVS isn't implemented yet (afaik?), it may be worth checking how the core/mpu/mm voltages that are used compare to those specified by efuse on the individual boards. Voltages high enough to allow weak-process dies to run stably cause excessive current and therefore heat on strong-process dies.

The efuse-specified voltages (in mV) can be found in the lower 12 bits of the following registers:
4a0021d8  vdd_core (OPP_NOM)
4a0021c4  vdd_mpu (OPP_NOM – 1 GHz)
4a0021c8  vdd_mpu (OPP_HIGH – 1.5 GHz)
4a0021a4  vdd_mm (OPP_NOM)
4a0021a8  vdd_mm (OPP_OD)

Matthijs