Modifications to spec.json file (in POA GitHub repo)
After downloading, you need to perform the command
chmod +x openethereum to be able to run the binary.
openethereum --chain poacore --no-warp
openethereum --chain poasokol --no-warp
--no-warp flag is optional: more information.
If you would like to limit or choose specific bootnodes, you can obtain the bootnodes.txt file from POA github. Enter all supplied enodes for the desired network separated by a comma, no space POA Core
git clone -b core https://github.com/poanetwork/poa-chain-spec.git
git clone -b sokol https://github.com/poanetwork/poa-chain-spec.git