I have a custom veroboard with a Pico1 (nonW) and some sensors. Draws about 80mA.
It is attached via USB to a headless Pi Zero W running Bullseye.
It had been running for 6 years powered by a rechargable battery that was acting as a UPS very successfully - as we have loads of power cuts.
I have a transaction count between the 2 devices and it had reached over 11,000,000. So it's all pretty solid.
Until ... the battery failed. Just stopped charging. I hadn't noticed. We had a power cut.
I then moved the whole system onto an APC BE650G2 UPS. Powering it from the USB feed.
I took the opportunity to update/full-upgrade the OS. All seemed to be good.
But now, I am getting serial errors randomly. Once I end up in the "except" clause, the error persists on each subsequent retry.
I quit the app and try to rerun it and this happens.
If I reboot the Zero using Shutdown-Reboot, I can then run as normal until the next serial failure - so power is never removed from the Pico or Zero.
Any ideas? The only thing I can think is that the OS update has changed something to do with the serial handling.
It is attached via USB to a headless Pi Zero W running Bullseye.
It had been running for 6 years powered by a rechargable battery that was acting as a UPS very successfully - as we have loads of power cuts.
I have a transaction count between the 2 devices and it had reached over 11,000,000. So it's all pretty solid.
Until ... the battery failed. Just stopped charging. I hadn't noticed. We had a power cut.
I then moved the whole system onto an APC BE650G2 UPS. Powering it from the USB feed.
I took the opportunity to update/full-upgrade the OS. All seemed to be good.
But now, I am getting serial errors randomly. Once I end up in the "except" clause, the error persists on each subsequent retry.
Any ideas? The only thing I can think is that the OS update has changed something to do with the serial handling.
Statistics: Posted by MarkDH102 — Sat Feb 07, 2026 7:35 am