Portisch firmware for EMF8BB1

Hi guys.
I am newcomer regarding a EMF8BB1 chip and Portisch firmware.
I have at home an old Sonoff RF-433 bridge, I flashed with Tasmota-sensors. Everywhere around I listen, how important is flash the old stock firmware within EMF8BB1 with the Portisch firmware, but nowhere are the requested files. They simply disappeared from the git.
Can somebody provide me with the files:
rfbridge_efm8bb1.hex
or Sonoff_RF_Bridge_EFM8BB1.hex

It been moved to the archive on GitHub.