Made 4 flashes through SD card using 2 different SD cards.

Still the board has the same 201905311059 latest firmware.

No way to downgrade.

i want to use an older firmware to test if i can alive a dead hashing board

https://bitcointalk.org/index.php?topic=5034849.0

Jumper flipped, both led are flashing after some seconds but the board has still this latest firmware installed!