nrf52840 builds not working

[jerryneedell]

[EDIT - problem is more widespread than just the done; see below -- @dhalbert]

I tried using one of the new RAYTAC-nrf52840 dongles? https://www.adafruit.com/product/5199 With the pre-installed firmware, I can see it with the nrf-connect app and see changes in the button state and well as set the LED on/off. I tried uploading CP from tip of main to it and it does not seem to boot - I see several errors in dmesg related to the file system. Does this device need some special handling?
dmesg errors

[439587.025403]  sdd:
[439587.027901] sd 8:0:0:0: [sdd] Attached SCSI removable disk
[439607.466351] usb 3-3.2: USB disconnect, device number 8
[439607.481272] blk_update_request: I/O error, dev sdd, sector 11 op 0x1:(WRITE) flags 0x0 phys_seg 8 prio class 0
[439607.481307] Buffer I/O error on dev sdd, logical block 11, lost async page write
[439607.481311] Buffer I/O error on dev sdd, logical block 12, lost async page write
[439607.481313] Buffer I/O error on dev sdd, logical block 13, lost async page write
[439607.481315] Buffer I/O error on dev sdd, logical block 14, lost async page write
[439607.481317] Buffer I/O error on dev sdd, logical block 15, lost async page write
[439607.481327] Buffer I/O error on dev sdd, logical block 16, lost async page write
[439607.481329] Buffer I/O error on dev sdd, logical block 17, lost async page write
[439607.481330] Buffer I/O error on dev sdd, logical block 18, lost async page write
[439607.481344] blk_update_request: I/O error, dev sdd, sector 269 op 0x1:(WRITE) flags 0x0 phys_seg 8 prio class 0
[439607.481347] Buffer I/O error on dev sdd, logical block 269, lost async page write
[439607.481349] Buffer I/O error on dev sdd, logical block 270, lost async page write
[439607.481379] blk_update_request: I/O error, dev sdd, sector 517 op 0x1:(WRITE) flags 0x0 phys_seg 1 prio class 0

[dhalbert]

I tried the dongle with:

• https://adafruit-circuit-python.s3.amazonaws.com/bin/raytac_mdbt50q-rx/en_US/adafruit-circuitpython-raytac_mdbt50q-rx-en_US-7.0.0-alpha.6.uf2: works and shows CIRCUITPY
• https://adafruit-circuit-python.s3.amazonaws.com/bin/raytac_mdbt50q-rx/en_US/adafruit-circuitpython-raytac_mdbt50q-rx-en_US-20210822-fdfcaf0.uf2: does not work

So a bisect is in order.

[dhalbert]

I tried a Feather nRF52840 with fdfcaf0 as well, and it doesn't work either. So something about the nRF builds has broken since alpha.6.

[dhalbert]

Bisected to

• d2860b5, which is Check background pending before sleep #5182

This is confusing because I thought I checked the nRF builds as part of doing audio testing on #5182.

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