In the 2017.1-2017.4 releases, when Linux is loaded it causes a hang in RPU code which was previously running without issues on Zynq UltraScale+ MPSoC devices.
For example, an R5 application configured for UART1 can be seen printing hello world on UART1. This runs smoothly until the Linux Kernel starts.
Once Linux loads, the R5 Application stops printing. At this point Linux loads and runs without issue on the APU.
This is not a bug in OpenAMP, it is related to device sharing between the APU and RPU.
To resolve this issue, add the below device-tree property in <proj-plnx-root>//project-spec/meta-user/recipes-bsp/device-tree/files/system-user.dtsi