The Travelpro Platinum Elite Regional Carry-On Rollaboard is specifically designed to fit most US carriers' underseat "personal item" size limits (usually 18x14x8"), and is on what appears to be clearance sale pricing directly from Travelpro (MSRP $279.99, Amazon $215.24 today, now $79.99, a 72.5% discount off MSRP, 63% off Amazon's price). Non-affiliate link.
A word of caution: I used the #RaspberryPi OS Installer on Windows to upgrade, and although it is supposed to erase all data on the microSD card, it clearly does not, as when I rebooted the system, /etc/shadow had my old account in it, which password I could not remember.
This should not cause much of a problem, but it's not what's advertised. The Installer should, IMO, format the card before writing the OS image. It also somehow automatically assigned the hostname I gave to the travel pihole.
OK, finally, my Pi 3B is fully updated and reconfigured. I had a few things go wonky, like apparently not typing in the new root password correctly, so I had to boot into single-user mode and do it all over again, but it's now running the latest version of Raspberry Pi OS and Pi-hole.
I hadn't made any major changes to my blocklists since exporting the config when I built the travel Pi-hole last month, so I had the config all ready to import.
Next, I need to update the travel Pi-hole.
OK, rather than buying a new microSD care and waiting for that to be delivered next week, I've shutdown the 3B, pulled the microSD card, changed my DHCP server to give out Quad9 for DNS so I can use my network, and I'm wiping the card and installing the latest version of Raspberry Pi OS (which just came out last week, so it will be newer than what is on my travel 4B Pi-hole).
I really should get a U3 card for the 3B, though. It's on a 16 GB U1 card, but the 3B can go faster than U1.
FML. I upgraded all teh packages on my Pi 3B, rebooted, and went to run "pihole -up", only to discover that Pi-hole no longer supports running on Raspbian 10 (buster). I would have sworn I was running Raspbian 11 (bullseye) on this machine. Now I have to do a complete overhaul of my main Pi-hole system, and I don't feel like it. What a PITA.
My travel Pi-hole system is the Pi 4B, definitely running Raspbian 12 (bookworm), because it's only two months old.
If only I had a spare microSD card...
At some point, I want to replace the Motorola cable modem/router with a plain cable modem unit, and I'll never buy another Motorola combination device again.
But I bought the Motorola 3.5 years ago because I needed to get out from under Comcast's outrageous $10/mo rental fee for their supplied modem/router. The government needs to make that kind of predatory pricing illegal.
Never rent a router from your ISP, it's a complete ripoff scheme.
I have a Motorola MG7540 combination cable modem/WiFi router, and that has to be one of the worst purchases I've ever made, because I didn't realize that Motorola gives Comcast 100% control over my router settings.
So, now I have to run a second WiFi router behind that one for my own privacy and security, and if I want to run an open wireless network, I have to get yet another WiFi router, instead of just opening up the Motorola one.
I'm already running too many routers, and don't want more.
The Whore of Blahbylon