Failure after update

General Beta 6.0
1

Started pihole -up on my pi3B running what was until today an up to date beta-v6 installation on an up to date RPiOS Bookworm. I was expecting the web interface to be updated. The update completed successfully on my pi4B installation.
My updated 4b is showing:

  • Core vDev (development-v6, 7206569b)
  • FTL vDev (development-v6, 23417040)
  • Web interface vDev (development-v6, 809a3aea)

Whilst the update on the 3B was running I was called away. When I got back the client PC with my ssh session had gone to sleep breaking the ssh session.
When I ssh into the 3B I have no working pihole. Any pihole command immediately returns me to the command prompt.
Is it possible to reinstall beta-v6 without going back and installing v5?
Both ftl.log and pihole.log have a block of repeated @^@^ at the end of the files.

2

Aagh!
Multiple entries in journalctl:
hwmon hwmon2: Undervoltage detected!
hwmon hwmon2: Voltage normalised
This is the probable cause of my pain.

3

Yes it most often is:

If you see warnings, switch to a higher quality power supply and cable. Low quality power supplies can corrupt storage or cause unpredictable behaviour within the Raspberry Pi.

https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#power-supply-warnings

4

I am using a POE switch and 5v POE splitters. There are no undervolt events on my Pi4B so it is either the switch port or the splitter. My investigation begins with switching ports.

5

Re-imaged and rebuilt from scratch. Monitoring journalctl