After replacing the battery and the power circuit, the screen is black

Hello.

I have recently replaced the battery in my Huawei Nova CAN-L01, along with the power circuit (the USB dock etc.).

The replacement wasn’t really hard but I have a major problem now.

I have tried to boot the phone, and the screen is just black. The backlight works, the OS boots fine (PC detects it), it responds to pressing the power button (backlight turns on or off), BUT no image is displayed.

My first thought was that the LCD got damaged since replacing the battery requires a lot of flexing around it, but It was not - I have tested another working LCD and it is also black.

I have also cleaned the LCD connector with IPA.

I have tried disconnecting the battery and holding the power button for over 5 minutes - didn’t work.

I cannot hard reset the phone since the screen is black and I can’t see the hard reset menu.

I have also tried booting with the old battery and old power circuit, but the result is the same.

Any clues of what could I do?