Redmi 4 Prime Slow Network

[Bertold Purda]

I just flashed Xiaomi.eu stable 8.2.1 rom on my Redmi 4 Prime, everything went alright, I restored from my mi cloud backup, I downloaded Apps easily, then after some time, I could not download anything, I can't download, can't open webpages.... I rooted the phone with supersu.zip, root is OK, used lucky patcher to patch Poweramp.... I think then the Internet slowed down...

 

[cesarmt]

I have the same problem with stable and developer roms: the phone only works in 2G networks... HELP!
Edit: There's a fix here https://xiaomifirmware.com/guides-and-tips/fix-missing-network-issue-redmi-4/