Repurposing a stack of old NUCs I came across an odd thing. The NUCs' keyboards worked fine under Linux, but none of the boot options presented in the UEFI splash screen worked.
After some experimentation I discovered that UEFI only sees USB keyboards from the two front ports. Other devices such as USB drives for booting work just fine.
Previous versions of Raspberry Pi Os (previously Raspbian) uses dhcpcd to configure static IP address. From the version 12 onward they defaulted to Network Manager instead. The official documentation unhelpfully suggests using your router to give it a static IP, but in various homelab use cases you might want the device to come up with a correct IP even if the DHCP server or something else failed upstream to the Raspberry Pi.
Many are familiar with Network Manager's GUI configuration, but its command line tool nmcli may be a new acquaintance.
After the default installation you will have a network configuration called "Wired connection 1" and it uses DHCP. We are going to replace that with static example IP of 192.168.123.50, using router .1 and the Google public DNS 8.8.8.8. Note that you either need to be root or sudo the following commands:
nmcli con mod "Wired connection 1" ipv4.address "192.168.123.50/24" ipv4.gateway "192.168.123.1" ipv4.dns "8.8.8.8" ipv4.method manual
Unless it gives you an error, you can activate this new configuration by:
nmcli con up "Wired connection 1"
The actual configuration is stored under /etc/NetworkManager/system-connections and can be edited with a standard text editor.
I was asked to look into freshly bought Roborock S8 in a case where the device's initial setup could not be completed. The owner had been running circles resetting anything from the vacuum cleaner to their phone's settings and had reached a total frustration with their tech support.
This device is technically curious. It's very expensive and it starts with claiming to be incompatible with pretty much anything, including 5GHz WiFi, longer WiFi passwords or anything but letters and numbers in them and the list goes on.
Because the vacuum cleaner couldn't handle 5GHz network, even with same named 2.4GHz network available, a separate network with just the wanted frequency range was set up for it. That didn't help. When setting up the device, the process progressed to the point where the vacuum cleaner was connecting to the WiFi and then it just stopped there.
A closer examination from Unifi dash board and on the firewall revealed curious behavior: the device did connect to its WiFi, got an IP, but then it just sat there. I assumed it would have wanted to call home for firmware upgrade, but there was no meaningful traffic outwards or towards the cellphone running its control app.
Looking at the frustratingly long shotgun approach the technical support had given them, one item caught my eye. They claimed the device is not compatible with networks that have their router at 192.168.8.1. Well that's certainly a curious limitation. This was also exactly what the owner had as their LAN address space. For the laughs, I changed the LAN's IP range to something else and would you look at that: the vacuum cleaner instantly called home and worked.