Hi, i can confirm who it works with a "clonic" microsoft receiver. I purchased one in ebay more than six months ago; and still working like a charm. I believe it cost me close to 9€ (a lot better price than the 25€ for the official one). Until now, using it with two controllers at the same time in Recalbox and no problems at all (with xboxdrvr activated).
@Marcos Clatablera I have the last version in Spanish, and no problem with that.
@rockaddicted Looks like we don't understand each other XD. The default core saves where it should, but the gpsp core saves in the same folder of the rom. I was not talking about changing the default core, as you say, i can change the core easily. I was thinking in fix the location to save in "/saves/gba" as well with the gpsp core. If you can test my PcEngineCD problem i would really appreciate that ^^. (English is not my native language, so sorry if i not express myself properly. It would be a lot worse if i try to do it in french :P)
@rockaddicted Yeah, as you can see in my comments about the new savedata folders, i have keep that in consideration already. I found the problem! Looks like now, the .sav file is been storage in the same folder as the rom, but for some reason the .state file is storage in the new savefile folder. I changed the core to gpsp, overwrite the .sav in "/recalbox/share/roms/gba", and now i can load my old save (phew). It has to be fixed in the second beta. About the PcEngineCD, yup, i have put the bios in. In fact, i was using a lot this system in previous betas (DraculaX, Gate of thunder, Mad Stalker, etc) without problems. I tried to do testings changing the core, but nope, it refuses to work. Normal pcengine games work fine as always.
@Voljega Perfect, i'm gonna try to make it work by hand. I never scrape the Fba/Mame games anyway, but it's good to know that. Thank you. @Subs After some testing, looks like the only system (at the moment) who can't read the old version savegames is GBA. I tried with some ps1 and n64 games and it works just well. I wanna try the rest of the systems soon. If i start a new game in a GBA game it saves without problems, but i don't wanna lose my previously save gamedatas. I tried saving ingame and then overwrite the file, without success. And i haven't find yet the way to make to work again the PcengineCD games, i don't know what to do. I tried with other syscard3.pce file, tried changing the cores... it just simply keeps throw me back to ES.
So, first of all; congrats for the awesome work made here. The amount of changes from the 3.3/17 is really huge. All the work here is pretty impressive. I have few problems with the version 4.0, one huge and the others... well, not a lot; but quite annoying. Since looks that the upgrade from 3.3 to 4.0 has to be manual; i made a backup (just in case), format the sd and a clean install of the 4.0. After re-put inside all the games; and all the savegames (a lot of files) in its "/save/especific-system" new location; i realized that some of them doesn't work anymore. 
Savestates don't either. (Example, Legend of zelda the minish cap, GBA) The PcengineCD games doesn't work too, with the same files working flawlessly in the 3.3 And, since "thegamedatabase.net" is down and there's a lot of roms to manually scrape; tried to paste my downloaded_images and gamelists folders in the new version, but i can't find it. Where is the location?
@Myop if this help to discard possible causes, modded Mayflash V1 here, and it works like a charm with the last beta. 
There are plans to fix the use of a ps3 controller via usb to work in the final release?
I don't speak french so sorry if some of this issues is already reported. Ain't a native english speaker either, so sorry about that. I have installed the beta 2 this morning. To this point i detected the next issues: -The n64 emulator still only configured with the ps3 control pad. Adding new controls to the system don't add its configuration. The games work, but notice some new graphical issues who are not present in the early version. Like flashing textures in some games (Mario 64 or F-zero). -The X button don't launch Kodi. It works through the menu, but not with the button. I had configured the menu and the recalbox.conf but no luck. The good news is; when i exit Kodi after launch it with the start button, it no longer blocks the controls back in emulationstation. -Once the custom resolution is set, the "Auto" option of the menu stops working properly and only shows custom. Not sure if i am the guy who messed up in an oversight, but is a thing to have in consideration. 4:3 and 16:19 still working fine after that -Shaders work, but borders not. -kodi is the 14.2 version; but i'm sure it will be the last version in the final release. I'll keep looking
Yeah, same here. XD That's why i decided to ask, this lack of information is starting to bugging me a little 
So... there is some update about the release of the 3.3.0?