Stock video app no longer works after reflashing ROM

[Android Central Question]

My mother bought myself and her a black Galaxy Tab S3 SM-T310 in 2014. Naturally it slowed down and over the last several months, she stopped using it completely. She's not exactly tech-savvy but was very interested in boosting the audio like I successfully did with mine through the default_gain.conf. She looked up some YouTube instructions,downloaded Odin etc to root the device. but long story-short...she flashed the wrong ROM either for a different country or for a phone and it became soft bricked coming up with the message.

"Firmware upgrade encountered an issue. Please reselect recovery mode in Kies and try again."

Thankfully, I restored it by downloading a UK Stock ROM and flashing it with Odin (It's originally a tablet bought in Republic of Ireland).

Everything seems fine with the exception of clicking the stock Video app and having no video play. When I download alternative video players with the PlayStore like VLC, all the videos on the tablet play fine. It just seems to be a problem with the app itself. Unfortunately, I sold my old tablet so I don't think I could flash the app with Titanium Backup even though I rooted her newly recovered device.

Thanks for any help. Could someone also if possible give the loudest possible values for the default_gain.conf file? Mother doesn't likes loud music but not in her ears

 

[B. Diddy]

Moved to the Tab 3 Rooting forum (it's Tab 3, not a Tab S3).