Recovery mode
FREE-WILi 2 has two RP2350 processors, each with its own USB bootloader, entered a different way. This page covers both, starting with the one that matters most when nothing else is working.
Last resort: hold red at power-up
If the device won't start, a firmware update went wrong, or you just can't reach it any other way: hold the red button while powering the device on. This forces the main RP2350 straight into its recovery bootloader, where it presents to a host PC as a USB flash drive ready for a fresh MAIN UF2 file.
This works because the red button is wired directly to the main RP2350's BOOTSEL line in the schematic — the same line the processor itself checks at boot to decide whether to run its flash image or wait for a UF2. It does not depend on any firmware being alive to handle it. A main processor with completely bricked firmware — corrupted flash, a crashing image, anything — will still drop into the bootloader when red is held at power-up, because the path is a wire, not code. This is the one to reach for when everything else has failed.
Don't confuse this with the other things holding red does — see Long-press actions. Holding red after the device is already running does something completely different: it puts the device to sleep. That's a separate mechanism, owned by the PIC, and it's how you power the device down day to day — it has nothing to do with the bootloader described here.
Everyday options
These work when the device is at least alive enough to run its own console or respond over USB. Reach for these first, and drop to the hardware path above only if they don't get you anywhere — or if the device won't boot enough to offer them at all.
Main processor bootloader (software)
Without touching any button, the main processor's bootloader is also
reachable from a menu inside the on-device serial console's settings, and
from the OneWili device API's "software reset to bootloader" command. Both
paths land in the same underlying function
(fwMenuSettingsHome::softwareResetToBootloader(), calling
reset_usb_boot(0,2)) that the hardware path above ultimately triggers too
— the difference is these require the main processor to already be running
well enough to reach its console or answer the API, where holding red at
power-up doesn't need the processor to be running at all.
Display processor bootloader
While on the main screen, long-press the blue button — but this only works while USB is connected and the charger reports that it's charging or has finished charging. Holding blue brings up a 5-second hold-progress dialog; on completion, the device shuts the charger down cleanly and reboots straight into the display processor's USB bootloader, where it presents as a flash drive for the display UF2 file (see Firmware update).
If a firmware update fails or a unit won't start
FREE-WILi 2's main processor has one automatic safety net: its second-stage bootloader checks for a valid flash partition table on boot, and if it can't find one, it automatically drops back into the main processor's USB bootloader (mass-storage mode) instead of trying to run a broken image. In that state, plugging the device into a host should present a flash drive again, ready for a fresh MAIN UF2 file.
If that automatic fallback doesn't help — for example, if whatever's broken is upstream of the check that triggers it — holding red at power-up (above) reaches the main processor's bootloader unconditionally, since it doesn't depend on any of this logic running at all. If you're stuck beyond the paths on this page, the FREE-WILi Discord is the place to ask.