We have using BMC to control reset of MCU. But BMC and MCU have difference main power.
So it cause a illegal reset level during power up.
We try to remove P3V3_A pull-up resistor (Figure 1) and P3V3_B pull-up resistor (Figure 2) get the difference result as attached waveform.
Does reset being left HI or left low during power up is OK?
Sorry for late reply.
I believe neither the P3V3_A and P3V3_B being pull-up resistor is Ok. Maybe you need a level translator to sync the power level of both ends.
Regarding to the level on INITX pin, please keep it low until internal RST release.