Read this and locate your error.
https://support.bitmain.com/hc/en-us/articles/220872007-Possible-problems-for-Antminer-Troubleshooting-for-S7-S9-L3-?mobile_site=true&page=8

I readed a bit into it and think this is for  you:
 https://enforum.bitmain.com/bbs/topics/2891

and a video about it from the bitmain support forum:
http://v.youku.com/v_show/id_XMTU0MDUwNTkzMg==.html?from=y1.7-1.2

Seems you have to manually flash your SD card.

yep, this should be the next step. Take a pin or needle and hold it as long into the "Reset-Button/Hole" (without much force!) until you hear the beep and see the red light. This should reset the Miner to factory settings. However, in case you have disrupted the upgrade process with unplugging it i'am not sure if this might be enough.... Hope so. Let us kow what happened and how things worked out.

The miner should've fully rebooted after 10 minutes. Try starting up your miner and checking if your miner's ip address changed. Use your router page to locate the new ip address.

That's the correct way to do it. There shouldn't be an issue unless you manually unplugged your miner while it was upgrading. Your IP address might've changed. Use an IP address scanner to find all devices on your network or use you router UI to find your antminer IP address.

You don't need to open it. Go to your miner's Upgrade page, Image, Choose File, Flash image:

NEW FIRMWARE UPDATE

Bitmain just released two firmware updates (Assuming that both required to get all features). One for showing fan speed and reducing rejected shares and the other increases hash rate by ~33% avg !!!!!!!!!!! (Getting 1040 H/S Average and 0 rejected shares)



Simply go here https://shop.bitmain.com/support.htm?pid=00720180519161243572MB78lOGz067A and download both firmwares. Flash you B3 with "Antminer-B3-20180519.tar.gz" first then after completing the upgrade flash it with "update_1000.tar.gz".


Please note that my B3's are running a bit hotter after the update also assuming that they're consuming more energy (Can someone confirm this please).

***NOT RESPONSIBLE IF THIS FIRMWARE BRICKED YOUR MINER. IT WORKED PERFECTLY FOR MY MINERS***


Please give me some of them merits if this post helped you  

so the second batch have already been delivered? can we assume  that the dificulty have  already increased right?

If anyone is interested here's my 2c on the bitmain antminer b3


https://youtu.be/O5jmj0LL6wM

I swapped out both fans for SILVERSTONE FHP Series SST-FHP141-VF, temps don't go above 50 and power at the wall dropped to 280w.

My next test will be to use 2x Phanteks PH-F120MP 120mm PWM High Static Pressure Radiator Fan and or 1x Phanteks + 1x SILVERSTONE. If needed I will put a honeycomb cell on the rear fan.