I'm seeing something really weird with my second Apollo (one of the final ones in Batch 1)
In eco mode, the Apollo sees roughly 2.2% to 3.0% hardware errors; but in balanced mode, 0.8% to 1.1%. Is this likely just silicon lottery, meaning this particular apollo needs more voltage? If so, what are the settings for each of the pre-baked modes?
Yea ECO mode is slightly more aggressive with voltage than the other modes, stock ECO values are 600MHz and 750mV...you should be fine if you bump it up to 775.
Were the stock ECO values changed at some point?
Looking from the MCU side file /var/local/apollo/hwmon/reg_voltage with the current firmware (in ECO mode), I can see it output 28, which according to
const voltageStep = parseInt((settings.voltage - 644) / 4.15)
(from /opt/apolloapi/src/configurator.js) results in 760 mV.
Yes hwmon controls default values which were undervolted slightly more in the latest firmware (AFAIR without looking at the source i think the step voltage was 26 which translates to around 750mv).