Controller Applet

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This is the controller applet which can be launched by Home Menu. Official sw uses this under nn::hid, and nn::hid::system with the "ForSystem" funcs. See AM_services#Library_Applets.

Library Applet Versions

System Version Value
[1.0.0+] 0x3
[3.0.0+] 0x4
[6.0.0+] 0x5
[8.0.0+] 0x7


This is "nn::hid::system::ControllerSupportArgPrivate". This is a 0x14-byte struct pushed for input storage. The data here is setup by sdknso internally without exposing it to the user.

PlayStartupSound is set to (Flag1 != 0) & (Flag0 != 0). Flag0/Flag1 are always 0 except with *ForSystem funcs in sdknso.

Offset Size Description
0x0 0x4 Size of this ControllerSupportArgPrivate struct.
0x4 0x4 Size of the storage following this one (#ControllerSupportArg or #ControllerFirmwareUpdateArg).
0x8 0x1 Flag0
0x9 0x1 Flag1
0xA 0x1 #Type
0xB 0x1 nn::hid::system::ControllerSupportCaller. Always zero except with ShowControllerFirmwareUpdateForSystem, which sets this to the input param.
0xC 0x4 Output from GetSupportedNpadStyleSet. With ShowControllerSupportForSystem on pre-3.0.0 this is value 0.
0x10 0x4 Output from GetNpadJoyHoldType. With ShowControllerSupportForSystem on pre-3.0.0 this is value 1.


This is "nn::hid::ControllerSupportArg". This is a 0x21C-byte (0x9C-byte with version <=0x2, 0x430-byte with version 0x7) struct pushed for input storage.

Layout with the original version:

Offset Size Description
0x0 0x1 s8 playerCountMin, must be >=0 and <=4.
0x1 0x1 s8 playerCountMax, must be >=1 and <=4.
0x2 0x4 Unknown u8 flags, non-zero for enabled.
0x6 0x1 Enables using the array at offset 0x7 when non-zero.
0x7 4*max_controllers Array of 4-byte entries for each controller, see below for total entries (max controllers). This entry contains individual u8s.
0x7 + 4*max_controllers 0x1 Enables using the ExplainText data when non-zero.

With both versions, the rest of the struct is an array containing 0x81-byte (0x21-byte with version <=0x2) entries. With version pre-0x7 there's 4 entries allocated, starting with version 0x7 there's 8 entries allocated. This contains the ExplainText string which includes the NUL-terminator. Each entry corresponds to a controller NpadId, starting with NpadId/controller 0.

Regardless of version, the default data for this struct is setup by setting u32 +0 to 0x01010400, u8 +4 to 0x1, with the rest being cleared as needed. sdknso itself only calls the func for this from ShowControllerStrapGuide, since that's the only time sdknso itself writes to ControllerSupportArg besides ExplainText (and is also the only case where the ControllerSupportArg is not user-specified).


This is "nn::hid::ControllerFirmwareUpdateArg". This is a 4-byte struct pushed for the input storage. The default value of this entire struct is 0.

Offset Size Description
0x0 0x1 ?
0x1 0x3 ?


Name Type value Description
ShowControllerSupport 0
[3.0.0+] ShowControllerStrapGuide 1
[3.0.0+] ShowControllerFirmwareUpdate 2

In sdknso there's two funcs which expose ShowControllerSupport: one which has a param for the output #ControllerSupportResultInfo, and one that saves that to stack and ignores it.

ShowControllerSupportForSystem has equivalent funcs for the above two funcs, which are the same except Flag1 is set to 1 and Flag0 is set to the input bool.

ShowControllerFirmwareUpdateForSystem is the same as ShowControllerFirmwareUpdate, except Flag1 is set to 1 and ControllerSupportCaller is set to the input param.


This is "nn::hid::ControllerSupportResultInfo". This is a 8-byte struct.


User-processes should push a common arguments struct, an #ControllerSupportArgPrivate, then #ControllerSupportArg or #ControllerFirmwareUpdateArg.

On success, an output storage should be popped, with size 0xC being used to read from there (sdknso ignores the actual storage size). When #ControllerSupportArg was previously used, the first 8-bytes are copied to the output #ControllerSupportResultInfo (which the user can ignore), otherwise it's ignored. The remaining u32 determines the Result: