PW3 (FW 5.16.2.1.1): KUAL Application Error after WinterBreak (Solved)

[micaco]

**PW3 (7th Gen, FW 5.16.2.1.1) – "Application Error" when launching KUAL after following the current WinterBreak guide**

Hi everyone,

I wanted to document an issue I encountered while jailbreaking my Kindle, together with the solution that finally worked for me.

**Device**

* Kindle Paperwhite 3 (7th generation)
* Firmware: **5.16.2.1.1 (4097470002)**

I followed the current official WinterBreak documentation:

* WinterBreak
* Hotfix (`Update_hotfix_universal.bin`)
* Run Hotfix booklet
* MRPI (modern devices)
* KUAL installation as described in the current guide (PEKI)

The jailbreak itself completed successfully. The Hotfix installed correctly and MRPI was working.

However, every time I launched KUAL I immediately got an **"Application Error"** (in my case the Kindle UI was in Spanish, but it is the standard KUAL Application Error).

To make sure it wasn't an installation mistake, I completely factory reset the Kindle and repeated the entire procedure from scratch using exactly the same downloaded files. The result was identical.

After several hours of troubleshooting, the solution that finally worked was:

1. Keep the existing WinterBreak, Hotfix and MRPI installation.
2. Remove the PEKI KUAL installation (`KUAL.sh`).
3. Install the classic KUAL Booklet instead using:
`Update_KUALBooklet_c6ac782_install.bin`
4. Copy the `.bin` to `mrpackages/`.
5. Run `;log mrpi`.
6. Reboot the Kindle.

After doing this, KUAL launched normally and has been working perfectly ever since.

I don't know whether this affects all PW3 devices running 5.16.2.1.1 or only some configurations, so I'm **not** claiming there is a general bug. I just wanted to document the exact symptoms and the workaround that solved it in my case.

Has anyone else seen this behaviour on a PW3 running 5.16.2.1.1? I'd be interested to know whether this is a known compatibility issue with the current PEKI-based installation or something specific to my device.

Many thanks to everyone maintaining WinterBreak, MRPI and KUAL. Without these projects, older Kindles would have a much shorter useful life.