I have a Batch 2 R4 that stopped hashing on one board, Miner status page still shows circles and not x, but very high HW on the board not hashing. Any ideas?

Please update the firmware: https://shop.bitmain.com/support.htm?pid=007201612090211421457I07aFFE0609
For details on how to upgrade the firmware please see the User manual: https://shop.bitmain.com/support.htm?pid=007201608300453591291gt4d83P0660

If that does not solve the issue then please first test the controller. You can switch the controller cables between hash boards. If the issue follows the cable then the controller is faulty and you can ship the controller to us for repair.

If that does not solve the issue then please test the hash boards one by one.

To test each hash board separately: keep the PSU connectors and controller cable on one of the hash boards connected and disconnect the cables from the other two hash boards. With the miner running you can see the status of the connected hash board.

Here is more detail: http://support.bitmain.com/hc/en-us/articles/226142788-Testing-hash-board-one-by-one

On the miner status screen defective chips are displayed as "xxx", "---" or " ASIC≠45(s7) or 63(s9)"

Once you know which part is defective please create a Repair ticket and ship the part back to us according to these instructions: https://cnshop.bitmain.com/workOrderGuide.htm

Sorry I am too lazy to check my R4B2. Mine just stopped hashing this morning where GH/s(RT) read 0 but everything else looked correct. Every share was rejected. Tried switching pools via MRR, no improvements. Tried flashing 1202 fw, it errored out and i freaked out too. but it rebooted itself and now everything's back up right.

I don't know what to say about these rigs. I hope they are of decent quality.