Android 5.1 UART problem

[sms1989]

Hi,

I have a NanoPi M2 and M3 work with Android 5.1 ...

I test example programs from GitHub (https://github.com/friendlyarm/AndroidHardwareAccess)

but SerialPortDemo not working and said "Fail to open /dev/ttyAMA2!" (ttyAMA2 for UART 3) ...

in Android 4.4 error not appear but it's not working

how can i use UART in Android 5.1 or Android 4.4

[v8dave]

I wonder if this is to do with policies as I see the same issue on my T3 and M3 boards running Android 5.1 when trying to use ttyUSB2 with a modem plugged in.

Try this from either ADB shell or from the UART as root (type su first)

setenforce=0

That should disable the policies until the next boot. See if your serial port now works.