Gidday JEDIKNT,
I have the Oppo 93 and 95 both with hardware mods which maybe similar to your newer 103.
If you have a hardware mod installed on your 103 you need to get in contact with the mod provider and ask them how to reflash your hardware mod via USB files. And they should provide them as part of customer service.
Also explain what you did by using an original Oppo Beta Firmware which I personally would never do as it might kill the mod or in your case lock it to unwanted region. Either way you may have killed that mod or your actual Oppo flashrom.
I also suggest if its safe to remove and you have the confidence to buy another hardware mod from a reputable provider online I can think of a denmark or danish guy and reinstall fresh and flash with their provided USB files and always check with them before using an Original Oppo Beta firmware.
As a last resort to save such a good piece of hardware you could ask Oppo UK to replace the whole circuit board and it would be as new.