So i have tried installing your firmware.
using SD card. Red and green light LEDs stay on. 20mins later they are still on. No difference.
Doing upgrade route from web page gives me Cannot Find Signature!!!

Miner Type   Antminer S9 SE
Kernel Version   Linux 4.6.0-xilinx-gff8137b-dirty #25 SMP PREEMPT Fri Nov 23 15:30:52 CST 2018
File System Version   Thu Jul 11 09:57:07 CST 2019

Any suggestions?

All Ii want to do is underclock this PoS.