hanguofu Posted August 4, 2021 Share Posted August 4, 2021 I am playing with X96 Max+ and it always stops at u-boot if its uart port is not connected . It is said that there is interference from uart port thus u-boot thinks it has received commands. Is that true ? Link to comment Share on other sites More sharing options...
Werner Posted August 5, 2021 Share Posted August 5, 2021 How about posting the actual output? Link to comment Share on other sites More sharing options...
hanguofu Posted August 5, 2021 Author Share Posted August 5, 2021 If the uart port is not connected , the u-boot stop after "Hit any key to stop autoboot: 2 1 0 " ---- it is just what I guessed. If I hooked up the uart port with a debug board , I saw no output from screen. But if I press "Enter" key , the u-boot shows "=>" and ready for commands . A "reset" command can make the u-boot to reboot . If the uart port is connected before power up , the u-boot boots normally. Link to comment Share on other sites More sharing options...
hexdump Posted August 5, 2021 Share Posted August 5, 2021 i saw things like this too - easy workaround is to put a usb to serial converter there and plug it into one of the usb connectors of the box - i guess its a problem with proper grounding resulting in noise on the serial line best wishes - hexdump Link to comment Share on other sites More sharing options...
Clonazepunk Posted August 5, 2021 Share Posted August 5, 2021 9 hours ago, hanguofu said: If the uart port is not connected , the u-boot stop after "Hit any key to stop autoboot: 2 1 0 " ---- it is just what I guessed. If I hooked up the uart port with a debug board , I saw no output from screen. But if I press "Enter" key , the u-boot shows "=>" and ready for commands . A "reset" command can make the u-boot to reboot . If the uart port is connected before power up , the u-boot boots normally. I had the same problem with some versions of the Amlogic S905W processor My workaround was to short the UART TX pin to ground using a small resistor. It fakes a UART connection and the boot continues If the step fails, try the same with the RX pin. Good luck! 1 Link to comment Share on other sites More sharing options...
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