KUAL + KOReader setup: the complete post-jailbreak Kindle workflow

You’ve jailbroken your Kindle — congratulations. Now the real fun begins. The jailbreak alone doesn’t do much; it’s the software you install on top of it that transforms the device. Here’s the complete walkthrough for KUAL, KOReader, the MKK bridge, and the screensaver hack — the four pillars of a proper post-jailbreak Kindle setup.

Step 1: Install MKK (Mobileread Kindle Kit)

MKK is the bridge between the jailbreak and everything else. It provides shared libraries and a certificate bundle that all third-party Kindle applications depend on — KUAL, KOReader, the screensaver hack, and USB networking all require MKK.

Copy the Update_mkk-<version>-install.bin file to the Kindle’s root directory via USB, eject, and go to Settings → Update Your Kindle. The update takes about 10 seconds and the device will reboot. After reboot, confirm MKK is installed by checking that the file mkk/developer.keystore exists in the USB root — you can view this when you reconnect the Kindle to your computer.

If the “Update Your Kindle” option is grayed out, the bin file is the wrong version for your firmware. MKK has separate builds for firmware 5.12.x, 5.14.x, 5.16.x, and 5.18.x — make sure you downloaded the correct one. No permanent harm if you try the wrong version; the update will simply fail silently.

Step 2: Install KUAL (Kindle Unified Application Launcher)

KUAL gives you a graphical menu inside the Kindle’s own UI. It looks like a book in your library; open it, and you get a list of launchable apps and scripts. It’s the Kindle equivalent of an app drawer.

Download the KUAL package and extract it. You’ll find two files: Update_KUALBooklet_<version>_install.bin (the booklet installer) and a KUAL.kual folder (the menu entries).
Copy the .bin file to the Kindle root, eject, and run Settings → Update Your Kindle. This registers KUAL as a “booklet” — a first-class application type in the Kindle OS — rather than the older “Kindlet” method that relied on deprecated Java applet support.
After reboot, copy the KUAL.kual folder to the extensions/ directory on the Kindle’s USB storage (create extensions/ if it doesn’t exist). This folder contains .json files that define KUAL’s menu structure.
A new book titled “KUAL” should appear in your library. Open it to see the launcher menu.

If KUAL doesn’t appear, check the .kual folder naming — it must be extensions/KUAL.kual/ (case-sensitive on the Kindle’s Linux filesystem). The booklet registration log is at extensions/MRInstaller/log/mrinstaller.log if you need to debug.

Step 3: Install KOReader

KOReader is the killer app for jailbroken Kindles. It supports EPUB, PDF with advanced reflow, CBZ/CBR comics, DJVU documents, and OPDS library browsing — all formats the stock Kindle reader can’t handle.

Download the Kindle build of KOReader from the official GitHub releases page. Choose the kindle variant (not kindlehf unless you have a Kindle Scribe or Oasis — hf stands for “high-resolution framebuffer”).
Extract the archive. Copy the koreader/ folder to the root of the Kindle’s USB storage.
Copy the extensions/koreader/ folder from the KOReader package into the Kindle’s extensions/ directory. This adds a KOReader entry to your KUAL menu.
Eject the Kindle, open KUAL from your library, and tap KOReader → Start KOReader.

The first launch takes about 20 seconds as KOReader builds its document cache. Subsequent launches are faster. KOReader uses its own file manager — navigate to your documents/ folder, find a book (EPUB, PDF, or anything), and open it. The rendering engine, Crengine, produces noticeably better typography than Amazon’s stock reader, with hyphenation, kerning, and ligature support you can fine-tune in the settings.

KOReader settings worth changing immediately

Status bar → Configure → Enable “Current time” and “Battery percentage.” KOReader’s status bar is far more useful than the stock one.
Screen → E-ink refresh settings → Set “Full refresh rate” to every 5 pages. KOReader’s partial refresh is good, but a periodic full refresh prevents ghosting buildup.
Device → Network → Connect to your Calibre content server or a public OPDS catalog. KOReader can download books directly over Wi-Fi.

Step 4: The screensaver hack

The stock Kindle screensaver is Amazon’s choice of author portraits or generic typography patterns. The screensaver hack replaces these with the cover of the book you’re currently reading (or any custom image).

Install the ScreenSavers Hack package from the MobileRead forums. Copy the .bin to the Kindle root, run Update Your Kindle, and after reboot, create a linkss/screensavers/ folder on the USB storage. Drop any PNG files (properly sized for your Kindle’s resolution — e.g., 1072 × 1448 for a Paperwhite) into this folder. The hack automatically scales and converts them.

For the “current book cover” mode, install the Cover Mode extension alongside the screensaver hack. It reads the book metadata from the Kindle’s database and generates a cover image on the fly. Enable it through KUAL under ScreenSavers → Cover Mode.

Step 5: The file manager — KUAL’s hidden superpower

KUAL ships with a built-in file manager called Kterm (a lightweight terminal) and USBNetwork (SSH-over-USB). Together, they let you browse the Kindle’s Linux filesystem from the device itself:

Launch Kterm from KUAL → Helper → Kterm. You get a full root shell with a virtual keyboard.
Use standard Linux commands: ls /mnt/us/documents/, cp, mv, rm, df -h to check free space.
For transferring files, toggle USBNetwork from KUAL and SSH in from your computer at 192.168.15.244. This is faster than USB mass storage mode and lets you transfer files without ejecting.

The combination of KUAL as launcher and KOReader as reader turns a locked-down Kindle into a genuinely open device — all with low risk, since none of these modifications touch the kernel or bootloader. If something goes wrong, a factory reset wipes everything clean and you start fresh.