ZyperOS vs Knulli on the GKD Pixel 2
Knulli is a fork of Batocera for many handhelds, and its May 2026 release lists the GKD Pixel 2 among its stable builds. Its docs cover all its devices at once and have no page for the Pixel 2, so some of what they describe may work differently on this one. This is Knulli beside ZyperOS, from each project's own code, docs and releases as of 7 November 2026, with a dash wherever no source speaks to the Pixel 2.
On this page
The short answer
- Pick Knulli if you want a Batocera-based system with Batocera's frontend and emulators, a scraper with three sources, video previews in its default theme, DraStic for the DS, and built-in menu music.
- Pick ZyperOS if you want Wi-Fi tested on the Pixel 2, games sent from any browser or over the USB cable, box art with no account, and battery care. ZyperOS 1.0.1 is out, with a card image and ZyperOS Installer.
Side by side
| ZyperOS | Knulli | |
|---|---|---|
| License | GPL-3.0, free | Buildroot's GPL-2.0-or-later; no license file of Knulli's own |
| Latest for the Pixel 2 | v1.0.1 (November 2026) | 20260511 "Scarab" (May 2026), a stable build |
| Systems | 40, and Ports | – |
| Wi-Fi on the Pixel 2 | Tested | – |
| Games over the network | Web page | Samba, SFTP |
| Games over the USB cable | Web page | ADB |
| Box art on the device | libretro, ScreenScraper, SteamGridDB | ScreenScraper, TheGamesDB, ArcadeDB |
| Video previews | Yes | Yes |
| RetroAchievements | Yes | Yes |
| Nintendo DS | DSperate built in, DraStic if you add it | DraStic (Advanced DraStic) by default, and melonDS |
| PortMaster | On the shelf | You install it |
| Menu music | Yes | Yes |
| Rumble | Yes | Yes |
| Side lights | Yes | – |
| Charge limit, charging screen | Yes | – |
| System updates | Over Wi-Fi or the USB cable, with roll back | A boot file for minor updates, a re-flash for major ones |
Installing
Knulli's 20260511 release has one file for the Pixel 2, knulli-rk3326-pixel2-scarab-20260510.img.gz, under its stable releases. Knulli's docs say to write it with an imaging tool such as Rufus, balenaEtcher, Raspberry Pi Imager or Win32 Disk Imager. That release needs a fresh write even over an older Knulli card, because its partition table changed. ZyperOS's release has a card image you write with any image writer, and ZyperOS Installer, which downloads and writes it for you. The install guide covers the steps.
Wi-Fi on the Pixel 2
This is the open question for Knulli on this handheld. Knulli's networking page, written for all its devices, lists USB Wi-Fi dongles with RTL8192CU or RTL8188EU chips, and recommends the TP-Link TL-WN725N, the same adapter ZyperOS is tested with. But in Knulli's build files the Pixel 2 does not have the Wi-Fi capability, and its Pixel 2 image uses a prebuilt kernel whose drivers the source does not show. So no source we read confirms Wi-Fi on a Pixel 2 running Knulli, and with it the scraper, RetroAchievements, PortMaster downloads and updates over the air.
ZyperOS loads its driver when the adapter goes in, and is tested on the Pixel 2 with the TL-WN725N. The Wi-Fi guide has the details.
Adding games
Knulli's docs offer Samba, which you turn on, and SCP or SFTP with its SSH service. They say a web page for file transfer is not supported and not planned. Over the USB cable, Knulli uses ADB, and its build gives the Pixel 2 that capability. ZyperOS opens one web page in any browser, behind a PIN, over Wi-Fi, its own network, or the USB cable. The adding games guide shows it.
Box art, previews and achievements
Knulli's scraper asks ScreenScraper, TheGamesDB and ArcadeDB over the network, and its default theme, Art Book Next, plays a scraped video in the game list. ZyperOS fetches covers from libretro with no account, ScreenScraper and SteamGridDB, and turns a cover into its video snap after a few seconds. Both have RetroAchievements built in; ZyperOS keeps a game's achievements on the card after its first start, so it plays offline.
DS, PortMaster and music
Knulli's RK3326 builds select Advanced DraStic and make DraStic the default for the DS, with melonDS too. PortMaster is not preinstalled: you install it from Knulli's Device Settings, with internet. Knulli has menu music built in, and your own MP3 or Ogg files in its music folder replace it. ZyperOS ships DSperate and runs DraStic if you add it, installs PortMaster from its Ports shelf with one press, and plays ten free tracks or your own. See the DS guide and the PortMaster guide.
Updates
Knulli's docs describe an update menu, then say there are no update servers yet. A minor update is a boot file you copy over; a major one is a full re-flash. ZyperOS's System Update downloads only what changed over Wi-Fi, into a second slot that rolls back if a new version fails. Without Wi-Fi, the File Transfer page brings it over the USB cable.
Which one to pick
Knulli brings Batocera's breadth and a stable Pixel 2 build, with DraStic, a three-source scraper and video previews. On this handheld, though, Wi-Fi is unconfirmed by any source, and much of Knulli leans on it. ZyperOS is narrower, but made for the Pixel 2, with tested Wi-Fi and transfers that also work over the cable. Each is a card, so try both.
Sources
- Knulli at 57afa66: README, COPYING, device capabilities, the Pixel 2 boot script, system Config.in, RK3326 defaults.
- Knulli release 20260511.
- knulli.org at 314b26f: Install, Network transfer, USB, Networking, Scraping, RetroAchievements, Updates, PortMaster, Background music, Themes.
- ZyperOS: the README and the user guide.