How can I modified device-tree to make IPQ5018 lan led blink?

[psherman]

Please see:

Ipq5018 qsdk cannot reserve configurations when exec sysupgrade

As stated earlier, the sdk you are using did not come from the OpenWrt project. It is a QSDK - Qualcomm sdk. Therefore, you need to reach out to Qualcomm for help. Their sdk is not supported here.