Okay so, for anyone experiencing this, flashing the latest firmware seemed to relieve the issue thus far.
The problem is that I met the same issue with firmware seems to be the latest (Tue May 22 20:08:17 CST 2018)...
main.c:13889: use critical mode to search freq...
driver-bitmain.c:2401: get PLUG ON=0x000000e0
driver-bitmain.c:2471: Find hashboard on Chain[5]
driver-bitmain.c:2471: Find hashboard on Chain[6]
driver-bitmain.c:2471: Find hashboard on Chain[7]
driver-bitmain.c:1840: set_reset_allhashboard = 0x0000ffff
main.c:2049: Check chain[5] PIC fw version=0x01
main.c:2070: chain[5] PIC need restore ...
main.c:2077: After restore: chain[5] PIC fw version=0x01
p.s. reset to factory settings via IP reporter button helped me to bring this miner back to work.
