Custom Rp2040 Board Device Descriptor Failed Error on Windows.

[atulravi]

I am working on a RP2040 Board in an UNO form factor as a drop-in replacement for an automation system with unos that are dying and am facing an issue where, I have built a custom RP2040 board. (Photos will be attached) When I plug it into windows, I get the device descriptor failed error code. In another prototype with the same chip that I had assembled before, the issue was due to 2 missing traces under the USB C port. But none of those exist in the current iteration. (Previous board issues here: https://www.eevblog.com/forum/microcontrollers/issue-building-custom-board-with-rp2040/) I have not changed the design much. I have only mapped the non-connected GPIOS to headers in the UNO formfactor. It is to be noted that the RP2040s were perfect since those board were assembled at a fab where they used a hotplate in my first prototype. But here, I am using Hot air instead. Could that cause an issue? Also, one mistake I made was not seeing that kicad did not connect the ground planes properly in the version I had fabricated. I have fixed that issue by adding a Bodge wire. Voltages are near perfect 3.34V on 3V3 pins and 1.08V on 1V1 pins. Oscillator seems to work fine. I have not tried using the debugger so far.  The CS Pin on the memory chip goes low when I press the bootsel pin on startup. Can anyone find any issue? (Like mentioned before, pics, scheme, gerbers are attached)

[SeanB]

Would suggest a Rossman of flux, and reflow the board first, to fix the few suspect dry joints there.

[atulravi]

Would suggest a Rossman of flux, and reflow the board first, to fix the few suspect dry joints there.

Rossmann level of flux later, I have a partially working board. Now the issue is, whenever I upload the micropython uf2 to the board, it disconnects but it reappears as a fat drive and not as a RP2040 micropython board.  Any idea of a probable solution?
 Update: I got rid of the BOOTSEL switch and added the micropython uf2. Now the device disconnected. But when I reconnect it, it is not recognised anymore. A flash issue maybe?

[atulravi]

Would suggest a Rossman of flux, and reflow the board first, to fix the few suspect dry joints there.

Rossmann level of flux later, I have a partially working board. Now the issue is, whenever I upload the micropython uf2 to the board, it disconnects but it reappears as a fat drive and not as a RP2040 micropython board.  Any idea of a probable solution?
 Update: I got rid of the BOOTSEL switch and added the micropython uf2. Now the device disconnected. But when I reconnect it, it is not recognised anymore. A flash issue maybe?

Picotool shows that micropython was uploaded and the flash size matches the chip that I have soldered. Now windows says unknown device when I flash the board with micropython and when I connect it windows fails to recognise it. Ubuntu as well. Hmm.....

[atulravi]

It turns out to have been an issue where the flash was acting up. replaced it and made sure it was not exposed to the heat of the hot-air gun directly and it worked! Thanks a lot for the help.