I don’t know if this is a bug or not but every time I try to press both Select+Start buttons together to open MAME internal settings menu (to change button settings, etc…), it crashes Retroarch.
Am I doing something wrong here or the internal MAME ui menu is no longer supported?
Sorry ImnoTapLumber if I did a mistake here. I’m a new Retroarch user so I don’t know what’s happening here. Why is my post being withdrawn?
EDIT: It seems that this Select+Star button combination is used to exit Retroarch and so it’s not “crashing” as I mentioned in my previous post.
But if this is the case, which combination do I have to press to open the internal MAME menu after entering a game?
It is my post i withdrawn 
I overlooked the “Android” and my post was about the behavior on windows.
I am sorry for confusing things, unfortunately i have no clue how it works on android.
Ok, it seems that Start+Select will bring up the mame-gui if you have set the Settings - Input - Hotkeys - Menu Toggle Gamepad Combo to something other than Start+Select
If you are searching for the ingame mame-menu, the key-combo should be Select+Retropad X or Y depending on the game.
(Never figured out, why on some games X and Y are swapped)
Hope this helps.
Thank you!! It works 