This system process handles displaying the error screens, such as "an error has occurred, the system needs shutdown". This can also display a register dump for exceptions, and info for fatal errors. (Normally the black-screen errors are displayed on retail, while the latter is displayed on development units.)

The register dump/fatal error info can also be written to nandrw/sys/native.log. On retail consoles, the system does not notify ErrDisp that any user-land exceptions occurred, ErrDisp is only notified for this on dev/debug units. Therefore, on retail consoles native.log only contains info from fatal errors. Starting with 5.0.0-11 ErrDisp no longer writes logs to native.log, except when the error-type is value 5 and when other checks with the errorinfo structure are successful (normally processes using this port never use error-type 5).

The bottom screen displays the error screen like "error has occurred", even with a development 3DS. The top screen can display the development error info, this is only displayed when UNITINFO bit0 is clear, for a development 3DS.

ErrDisp handles "returning" to Home Menu via NSS:RebootSystem, which triggers a hardware system reboot.

ErrDisp error port "err:f"

Command Header Description
0x00010800 ThrowFatalError(0x80-byte errorinfo)
0x00020042 (size, (size<<14) | 2, errorinfoptr) This is similar to cmd1, except with this the input buffer is copied to final output errorinfo+0x80 instead of +0x0, via the ARM11 kernel. Max size is 0x100. ErrDisp doesn't do anything in the cmd-handler for this command at all, besides checking the command header and buffer header.

output, where *((u8*)errinfo) == 4

Entry Format string Format args Description
PID 0x%08X_0x%08X *(u32*)(errinfo + 0x10), *(u32*)(errinfo + 0x14) Process ID
REV %d *(u16*)(errinfo + 2) | (*(u8*)(errinfo + 1) << 16) ?
AID 0x%08X_0x%08X *(u32*)(errinfo + 0x18), *(u32*)(errinfo + 0x1C) Application ID?
RSL 0x%08X *(u32*)(errinfo + 4) Error code
Level %d *(u32*)(errinfo + 4) & 0x80000000 ? (*(u32*)(errinfo + 4) >> 0x27) - 0x20 : *(u32*)(errinfo + 4) >> 0x27 Error code level
Summary %d (*(u32*)(errinfo + 4) & 0x7E00000) >> 21 Error code summary
Module %d (*(u32*)(errinfo + 4) & 0x3FC00) >> 10 Error code module
Desc %d (*(u32*)(errinfo + 4) << 22) >> 22 Error code description
? %0.*s 0x2E, for (int i = 0; i < 2; i++) (errinfo + (((i << 3) - i) + (i << 4)) << 1) + 0x20 ?
Datetime %04d/%02d/%02d %02d:%02d:%02d ? ?