We had an issue with i.MX6 automotive quad core crashing during boot but only when cold (a few boot crashed as warm as 10C to 15C) and when VDDARM_CAP dropped from 1.2V (792MHz) to .925V (assume 396Mhz while IO was being set up). Also crashes during the same .925V condition on power down.
Found that reducing VDDARM_IN and VDDSOC_IN voltages from 1.475V to 1.3V have significantly lowered the temperature at which crashes occur.
I'm not sure this fixes the issue correctly since the condition for VDD_CACHE_CAP must be less than 200mV above VDDARM_CAP is violated with either VDDARM_IN supply level during the crash periods (when LDO is at .925V).
Why is reducing the VDDARM_IN and VDDSOC_IN input levels making a difference at the temperature that the boot crashes occur?
Appreciate any insight into why this works or other ways to address the issue.