If I connected the serial port with my device through GPIO pin 8 and 10 (UART_AO_A_TXD, UART_AO_A_RXD), the Radxa Zero with Debian 10 failed to boot.
If I removed my device from the serial port, zero can boot.
After booting, I connected my device to the UART port, it worked well through /dev/ttyAML0.
Any suggestions? Many thanks!