My son found a P20 Pro CLT-L04 4 month ago (Canada). The phone is FRP protected. I tried everything but I can't reset the phone. If I understand well, I have to downgrade the firmware. So I downloaded the CLT-L04_default_ca (Charlotte 18.104.22.168), plugged a hardrive on the USB-C to USB adapter. I always ended up after 1minute to the "Software Install Failed". Seems the phone read well the hard drive as I ear it spinning (it has his own power supply) and scratching, so something happen.
Any idea? Should I try another firmware.
I have on my HD: "dload->CLT-L04_default_ca->update_sd_CLT-L04_default_ca.zip"
There is also a update_sd.zip file in the dload folder.
Multi-Tool told me: CLT-L04 22.214.171.1243 (C792E9R1P11).