TMDSCNCD263P: AM263Px Control Card - Blackbird PMIC LDO2_OUT Issue

I am working on UART communication using UART1 of the AM263Px (TMDSCNCD263P, PCB: PROC159B) control card connected to the launch pad (Docking Unit: TMDSHSCCDOCK-AM263, PCB: PROC148A). While debugging, the controller is generating UART data, but no signal is observed on the HSEC connector pins. From the schematics, UART1 from the SoC is routed through a LIN MUX/DEMUX (SN74CB3Q3257PWR) controlled by an IO expander (TCA6424ARGJR). We found that the LIN MUX/DEMUX is not powered, as its Vcc is supplied from the LDO2_OUT rail of the Blackbird PMIC (TPS6538600QDCARQ1). The TI documentation available is not sufficient to debug this issue further, so we need detailed technical documentation on the Blackbird PMIC operation.