If the firmware cannot be upgraded or the firmware upgrade fails, please check the following possible causes and solutions.
1. Incorrect firmware version.
Make sure you upgrade the correct firmware version according to the miner model.
2. Secure firmware and non-secure firmware.
If the backstage of the miner shows "System Upgrade Failed-Cannot Find Signature!!!" It means that the firmware you want to upgrade is not a secure firmware.
3. Incompatible browsers or browsers with excessive cache.
Use a different browser to test, we recommend using Google Chrome or Firefox and clearing the cache. If unsuccessful, please use a different PC or laptop.
4. The miner was hacked.
Read this article for more information: How to prevent and remove viruses, malware and remote attacks on Antminer?
5. There is a problem with the control board.
(1) Reset the control board;
(2) Use the SD card to restore the program;
(3) Replace with a good known one to test.