I am not sure what isn't clear. Figure 21 of the RP2350 datasheet seems clear and simple enough to me. To provide your own 1V1 source and disable the on-chip regulator which would otherwise provide that -Although the datasheet is not clear
1) Remove the VREG_LX inductor
2) Connect VREG_FB to GND
3) Supply 1V1 to the three DVDD pins plus the 1V1 rail on the PCB
It wouldn't surprise me if leaving VFREG_FB connected to 1V1 and/or DVDD pins has little or no affect on anything. Even floating it may only cause higher current consumption. And that wouldn't much matter once the regulator is shut down by writing a 1 to the VREG register’s HIZ field. I admit I haven't tried either.
So long as the VREG_LX inductor is removed and a suitable 1V1 is provided externally, with its GND connected to Pico 2W GND, I cannot see why the Pico 2W wouldn't operate as expected and respond to the BOOTSEL button.
If it doesn't, my guess would be there was some error made or damage done in modifying the PCB. But maybe VREG_FB does need connecting to GND to prevent interference with correct operation.
Statistics: Posted by hippy — Mon Jan 12, 2026 4:19 pm