Try again using the recovery command https://github.com/arduino/openwrt-yun#recovering together with nohup
MAKE_JOBS=5 nice -n 10 nohup make -j $MAKE_JOBS V=s &
This will create a nohup.out file with all the output. You can see what's going on with
tail -f nohup.out
Once terminated, please, upload the file somewhere so we can read it