Main takeaway: setting up DSpico for use on Nintendo DSi is complicated and unintuitive; in stock form, as it arrives from AliExpress, it effectively does not offer full DSi support.
DSpico can work on Nintendo DSi, but on an unmodified system it can only launch through a whitelist-compatible entrypoint (WRFU).
Because of this, the DSi menu shows the WRFU icon instead of the selected game's icon, although this has no practical effect on functionality.
The DSi firmware for DSpico (dsimode.nds) is stored entirely in the RP2040's flash memory, so the size of the entrypoint ROM is strictly limited by the built-in storage.
Most full-size DS/DSi games do not fit in flash, so in practice only a compact bootloader or payload is written there.
The microSD card is used to load games and homebrew after DSpico starts, but it cannot act as the primary boot source on DSi because of whitelist restrictions and SD timing requirements.
A typical boot sequence looks like this: WRFU → launch DSpico → start the loader → launch games from microSD.
The _picoboot.nds file acts as an autoloader from microSD and can automatically launch a selected game or homebrew after DSpico starts.
_picoboot.nds does not affect the cartridge icon or name shown in the DSi menu — those are always determined by the primary whitelist ROM (WRFU).
Attempts to replace WRFU with other ROMs, including DSiWare, usually fail: the cartridge may not be detected or may fail DSi checks.
Building and preparing DSpico firmware is often complicated by network restrictions; in some cases a VPN is required to download dependencies and repositories.
