Change retroarch from app to game. Put files anywhere retroarch has access to. Have retroarch point to the bios file in settings. You can also ftp in and do this or file explorers with access.hi all, I have a very strange problem regarding the Xbox device portal .... I updated my Xbox One few days back, then switched to dev mode, Retroarch would not start (took too long to load error). Today I installed the latest version (RetroArch-msvc2019-UWP_x64), set it up, pointed browser to ROMs, played games, etc .... when I tried to upload some BIOS files to the LocalState > system folder via FireFox web browser the spinner went round but nothing uploaded.
Thing is, I can infact upload files to other Retroarch folders via the portal but the system is not accepting files, therefore I cannot play Neo Geo arcade, PS1, SEGA Naomi .... has anyone else encountered this & has a solution ? Its been many months since I uploaded via the portal using Firefox, maybe something has broken in the latest Firefox version ?
I have found this post but the fix method described didnt work: https://forums.hololens.com/discussion/9283/i-can-no-longer-upload-files-through-device-portal