diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e1ba3465..80af48c02 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,7 +24,8 @@
* Removed the ScraperHaltOnInvalidMedia option and corresponding menu entry as it has been superseded by the HTTP error code logic
* Added a ScraperIgnoreHTTP404Errors option that can be manually set in es_settings.xml to ignore 404 errors (resource not found)
* Added Mednafen standalone as an alternative emulator for the gb, gba and gbc systems
-* Added Mesen standalone as an alternative emulator for the multivision and sg-1000 systems on Linux, Unix and Windows
+* Added Mesen standalone as an alternative emulator for the gamegear, mastersystem, multivision and sg-1000 systems on Linux, Unix and Windows
+* Set Mesen standalone to specifically run in Super Game Boy mode for the sgb system on Linux, Unix and Windows
* Added the melonDS DS RetroArch core as an alternative emulator for the nds system
* (Linux) Added support for the AppImage release of Vita3K
* (Linux) Added support for the Flatpak release of puNES
@@ -62,6 +63,8 @@
* An extra space character was appended to text elements when setting the systemdata property to gamecountGames or gamecountGamesNoText
* Theme loading debug output would sometimes print incorrect paths when the configuration included files using variables
* Font textures were sometimes updated with empty glyhps which generated OpenGL errors on some mobile GPUs
+* The custom collection editing popup did not show the correct button name if the controller type was a PlayStation variant
+* The UI mode confirmation dialog did not show the correct button descriptions if the controller type was PlayStation 1/2/3
## Version 2.2.1
diff --git a/INSTALL-DEV.md b/INSTALL-DEV.md
index 8ff4a4a40..3fe63c65c 100644
--- a/INSTALL-DEV.md
+++ b/INSTALL-DEV.md
@@ -1733,6 +1733,8 @@ The es_systems.xml file on Android utilizes variables heavily to implement the _
There are two main ways to pass options to emulators, using _extras_ or using the _data_ URI. There can only be a single data URI but there can be an arbitrary amount of extras. To understand more about the way this works, you can read about the _putExtra()_ and and _setData()_ functions here:\
https://developer.android.com/reference/android/content/Intent
+`%MIMETYPE%` - Sets an explicit MIME type, which you need to assign using an equal sign such as %MIMETYPE%=text/plain. You will rarely, if ever, need to set an explicit MIME type so this variable is of limited use. By default Android will set the MIME type to application/octet-stream which is normally what you want.
+
There are three approaches to passing game ROMs to emulators by using the following variables:
`%ROM%` - Replaced with the absolute path to the selected ROM. This is a traditional method to provide the game ROM and its use will likely decrease or go away completely long term as emulators move to more modern methods.
diff --git a/USERGUIDE-DEV.md b/USERGUIDE-DEV.md
index 1c9bb1eae..d9ae009da 100644
--- a/USERGUIDE-DEV.md
+++ b/USERGUIDE-DEV.md
@@ -4010,7 +4010,7 @@ The **@** symbol indicates that the emulator is _deprecated_ and will be removed
| gamate | Bit Corporation Gamate | MAME - Current | MAME **(Standalone)** | Yes | Single archive or ROM file |
| gameandwatch | Nintendo Game and Watch | MAME Local Artwork **(Standalone)** | MAME **(Standalone)**,
Handheld Electronic (GW) | No | See the specific _LCD handheld games_ section elsewhere in this guide |
| gamecom | Tiger Electronics Game.com | MAME - Current | MAME **(Standalone)** | Yes | Single archive or ROM file |
-| gamegear | Sega Game Gear | Genesis Plus GX | Genesis Plus GX Wide,
Gearsystem,
SMS Plus GX,
PicoDrive,
Mednafen **(Standalone)**,
ares **(Standalone)** | No | Single archive or ROM file |
+| gamegear | Sega Game Gear | Genesis Plus GX | Genesis Plus GX Wide,
Gearsystem,
SMS Plus GX,
PicoDrive,
Mednafen **(Standalone)**,
Mesen **(Standalone)** [LW],
ares **(Standalone)** | No | Single archive or ROM file |
| gb | Nintendo Game Boy | Gambatte | SameBoy,
SameBoy **(Standalone)**,
Gearboy,
Gearboy **(Standalone)** [LW],
TGB Dual,
Mesen-S,
Mesen **(Standalone)** [LW],
bsnes,
mGBA,
mGBA **(Standalone)**,
VBA-M,
VBA-M **(Standalone)**,
Mednafen **(Standalone)**,
ares **(Standalone)**,
SkyEmu **(Standalone)** | No | Single archive or ROM file |
| gba | Nintendo Game Boy Advance | mGBA | mGBA **(Standalone)**,
VBA-M,
VBA-M **(Standalone)**,
VBA Next,
gpSP,
Mednafen **(Standalone)**,
ares **(Standalone)**,
SkyEmu **(Standalone)** | Yes for ares | Single archive or ROM file |
| gbc | Nintendo Game Boy Color | Gambatte | SameBoy,
SameBoy **(Standalone)**,
Gearboy,
Gearboy **(Standalone)** [LW],
TGB Dual,
Mesen-S,
Mesen **(Standalone)** [LW],
bsnes,
mGBA,
mGBA **(Standalone)**,
VBA-M,
VBA-M **(Standalone)**,
Mednafen **(Standalone)**,
ares **(Standalone)**,
SkyEmu **(Standalone)** | No | Single archive or ROM file |
@@ -4029,7 +4029,7 @@ The **@** symbol indicates that the emulator is _deprecated_ and will be removed
| macintosh | Apple Macintosh | MAME Mac SE Bootable **(Standalone)** | MAME Mac SE Boot Disk **(Standalone)**,
MAME Mac Plus Bootable **(Standalone)**,
MAME Mac Plus Boot Disk **(Standalone)**,
Basilisk II **(Standalone)**,
SheepShaver **(Standalone)** | Yes | See the specific _Apple Macintosh_ section elsewhere in this guide |
| mame | Multiple Arcade Machine Emulator | MAME - Current | MAME 2010,
MAME 2003-Plus,
MAME 2000,
MAME **(Standalone)**,
FinalBurn Neo,
FinalBurn Neo **(Standalone)** [LW],
FB Alpha 2012,
Flycast,
Flycast **(Standalone)**,
Flycast Dojo **(Standalone)**,
Kronos [LW],
Model 2 Emulator **(Standalone)** [W],
Model 2 Emulator [Suspend ES-DE] **(Standalone)** [W],
Supermodel **(Standalone)** [LW],
_Shortcut or script_ | Depends | See the specific _Arcade and Neo Geo_ section elsewhere in this guide |
| mame-advmame | AdvanceMAME | AdvanceMAME **(Standalone)** [LW] | | Depends | See the specific _Arcade and Neo Geo_ section elsewhere in this guide |
-| mastersystem | Sega Master System | Genesis Plus GX | Genesis Plus GX Wide,
SMS Plus GX,
Gearsystem,
PicoDrive,
Mednafen **(Standalone)**,
ares **(Standalone)** | No | Single archive or ROM file |
+| mastersystem | Sega Master System | Genesis Plus GX | Genesis Plus GX Wide,
SMS Plus GX,
Gearsystem,
PicoDrive,
Mednafen **(Standalone)**,
Mesen **(Standalone)** [LW],
ares **(Standalone)** | No | Single archive or ROM file |
| megacd | Sega Mega-CD | Genesis Plus GX | Genesis Plus GX Wide,
PicoDrive,
ares **(Standalone)** | Yes | |
| megacdjp | Sega Mega-CD [Japan] | Genesis Plus GX | Genesis Plus GX Wide,
PicoDrive,
ares **(Standalone)** | Yes | |
| megadrive | Sega Mega Drive | Genesis Plus GX | Genesis Plus GX Wide,
PicoDrive,
BlastEm,
BlastEm **(Standalone)** [L],
Mednafen **(Standalone)**,
ares **(Standalone)** | No | Single archive or ROM file |