For BOOT_SEL0#, an 1K Ohm series termination resistor is provided in (OSM Pin) CPU, initially the boot selection status will be read, and later CPU will start to transmit data through debug UART (UART_CON_TX) and it is recommended to use 220E series resistor with GND pin while using a 2.54mm Jumper.
For BOOT_SEL1#, should go low only during flashing time and while booting its status will be high so it won’t affect the UART function.
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Please find the detailed G50S product information in the below link,