I think I bricked my A3 non Pro. I firmware upgraded the light rom with sp flash toot and it said ok.
Now screen stays black volume up + power doesn't work.
Most likely you can recover from this.
Post #6 clearly states "I use umidigi A3. Will it work for me Absolutely not. This thread is reserved exclusively to the Umidigi A3 Pro"
So, why would you flash it to your NON PRO?
The good news is that you can get a stock NON PRO Rom and probably flash that and get your phone back.