Modern printers don't just sit on a desk. Many join your Wi-Fi, link to the maker's app and cloud, and run firmware that gets updated over the internet. That's handy when you own one, and it adds a step when you buy one used. The seller needs to take the printer off their account, and you need to know what firmware you're getting. Each maker handles it differently.
Why it matters
A printer that's still bound to the seller's account can be awkward or impossible to add to yours. And while it's bound, the seller's account can still reach it. Firmware matters for a different reason. It decides which slicers and add-ons work, and on some printers an owner may have replaced the stock firmware with something custom. Both are easy to sort out with a few questions and, usually, a reset before the printer goes in the box.
Bambu Lab
Bambu's printers are the most tied to their maker's cloud, so they need the most care. Bambu's packing guide says to do a factory reset before packing, from Settings, then Factory Reset, "to ensure your account is removed from the machine." Ask the seller to do exactly that. On the X1 Carbon, Restore to Factory Settings sits on the same settings page as LAN Only mode.
In January 2025 Bambu added an authorization system to its firmware, starting with the X series, with the P and A series planned to follow. It requires authorization for binding and unbinding the printer, starting prints, firmware upgrades and remote control. Status reporting and printing from an SD card are exempt. Third-party slicers like OrcaSlicer send jobs through Bambu's Bambu Connect app instead. After criticism, Bambu said the update was optional and described two modes for the X1, P1, A1 and A1 mini. The standard mode needs neither internet access nor an account, and Developer Mode leaves the printer's local network channels open, without Bambu support. So ask which firmware a used Bambu runs, and whether it's in LAN Only or Developer Mode if you plan to use OrcaSlicer or Home Assistant.
Bambu also warns that a printer whose serial number isn't registered can't be bound, which can happen if its main board was replaced without going through Bambu support. If a listing mentions board repairs, ask how they were done.
Prusa Research
Prusa makes this easy. On Buddy firmware 6.4.0 or later, which covers the MK4S, MK4, MINI+ and XL, the reset menu has an Ownership transfer preset. It resets the network and user profiles, including Wi-Fi, Ethernet, Prusa Connect and PrusaLink settings, but keeps the hardware configuration, calibrations and statistics. That's the reset to ask for, because it leaves the print-time statistics in place for you to read.
A full factory reset, by contrast, wipes those statistics. On the MK3S+, the reset menu offers separate options, including one that erases the statistics and a Shipping prep option. The MK3S+ has no network built in. Prusa's firmware is open source, so a printer running custom firmware is possible. Ask which version it runs.
The SL1S resin printer has its own firmware, with Prusa Connect support. Its factory reset, under Settings, Firmware, Factory reset, clears the statistics, including total print time, so read them before the seller resets it. A photo of that screen taken before the reset is all you need.
Creality
Creality's newer printers run Creality OS, its own firmware built on Klipper, the open-source printer firmware. The Ender 3 V3 KE, K1 and K1 Max all connect to Creality Print and Creality Cloud, but the cloud is optional, and LAN and USB both work. Ask the seller to unlink the printer from their Creality Cloud account before it ships.
Creality publishes the K1 series' Klipper source and an official root-access guide on GitHub, so plenty of K1s have been rooted to run standard Klipper tools. A rooted printer is fine to buy, as long as you know, so ask whether a K1 or K1 Max is rooted or stock. KE owners can also swap in standard Klipper for Creality's.
Elegoo and Anycubic
The Elegoo Neptune 4 Pro and Neptune 4 Max ship with Klipper preinstalled and a web interface on your network. The Neptune 4 Max runs Elegoo's own form of Klipper, which can't be updated from the main Klipper project, so ask whether the seller has changed anything. There's no cloud account to remove, but ask for any saved Wi-Fi details to be cleared.
Anycubic's Kobra 3 runs what Anycubic calls Kobra OS and works with its app. On the Kobra 2 Pro, app control needs firmware 3.0.5 or later. Ask the seller to remove an Anycubic printer from their app account before it ships.
Resin printers vary. The Photon Mono 2 and Mono X 6Ks print from USB only, with no account to worry about. The Photon Mono M5s, Mars 4 Ultra and Saturn 4 Ultra connect over Wi-Fi, so ask for saved networks to be cleared and any app account unlinked.
UltiMaker
UltiMaker's printers are managed through UltiMaker Cura and Digital Factory. Ask the seller to remove the printer from their Digital Factory account. Also know that UltiMakerCare service plans are tied to the serial number and can't be resold or transferred, so a seller's remaining plan doesn't come with the printer.
What to ask, in one list
- Which firmware version is it running, and is it stock or custom?
- Has it been removed from your account, and can you reset it before shipping?
- On a Prusa, can you use the Ownership transfer reset so the statistics stay?
- On a Bambu, is it in LAN Only or Developer Mode, and has the main board ever been replaced?
- On a Creality K1 or K1 Max, is it rooted?
- Have you cleared any saved Wi-Fi networks?
- On a Wi-Fi resin printer, have you unlinked it from the maker's app?
- On an UltiMaker, has it been removed from Digital Factory?
For the hardware checks, see how to check a used 3D printer.
