When I try to update the Firmware I get "The uploaded image file does not contain a supported format. Make sure that you choose the generic image format for your platform."
You will get this error if you are trying to flash the s9 miner with default firmware in the Braiins OS WebGUI.
There is no way back if you flash the Braiins OS in the WebGUI but you can flash it through SD card as suggested above.
There is no SD card in the slot. Also, I wouldn't say that I am locked out as I can change settings and the unit works. I just can't change the firmware.
I am interested in trying the SD card but I don't see firmware for an S9. Is there no way to just do a hard reset? I have tried the IP button and reset and it still boots to BraiinsOs. Thanks again!
If there is no SD card in the slot you need to provide. Buy a new SD card and make a bootable SD card and put the default firmware the guide is already posted by mikeywith.
What you need to do is to use the SD card to make a bootable SD card(Where the default firmware of antminer s9 is installed) to flash the control board of s9 miner. It is likely you are going to format your PC or laptop to install a fresh OS.