Hi all,
I'm working with a custom RP2040-based board. I can successfully enter BOOTSEL mode, mount the board as a USB drive, and flash a .uf2 firmware file. After flashing, the code runs correctly - I can control LED's and other devices.
However, after a power cycle or reset, the board is no longer detected over USB, and the previously running code does not start again. It seems like the program is not executing at all, even though the flashing step reports success. I can not pick it up on the serial terminal, and Thonny indicates it cannot connect (Putty as well). I uploaded the standard uf2 to program via Thonny, but then switched over to the VS code SDK to flash the code as a uf2.
I’ve carefully checked all hardware components against the RP2040 datasheet — including power rails, crystal selection, reset pin, USB D+/D− routing, and resistor values. Power is stable, and the LED code does execute immediately after the .uf2 is flashed, which suggests the firmware is valid.
This leads me to believe the issue is with boot behavior, possibly related to USB initialization or how the program is linked/flashed.
Has anyone encountered a similar issue where the firmware runs once after flashing, but fails to persist after a reboot?
Thanks in advance for your insights!
I'm working with a custom RP2040-based board. I can successfully enter BOOTSEL mode, mount the board as a USB drive, and flash a .uf2 firmware file. After flashing, the code runs correctly - I can control LED's and other devices.
However, after a power cycle or reset, the board is no longer detected over USB, and the previously running code does not start again. It seems like the program is not executing at all, even though the flashing step reports success. I can not pick it up on the serial terminal, and Thonny indicates it cannot connect (Putty as well). I uploaded the standard uf2 to program via Thonny, but then switched over to the VS code SDK to flash the code as a uf2.
I’ve carefully checked all hardware components against the RP2040 datasheet — including power rails, crystal selection, reset pin, USB D+/D− routing, and resistor values. Power is stable, and the LED code does execute immediately after the .uf2 is flashed, which suggests the firmware is valid.
This leads me to believe the issue is with boot behavior, possibly related to USB initialization or how the program is linked/flashed.
Has anyone encountered a similar issue where the firmware runs once after flashing, but fails to persist after a reboot?
Thanks in advance for your insights!
Statistics: Posted by Jakespico — Fri Jul 18, 2025 12:03 pm