WinterBreak v2.1.0 silently fails to install on 11th gen (C2V2L3) FW 5.15.1 — partial install (fbink dropped, no winterbreak.log / MNTUS_EXEC / pubdevkey01.pem)

## WinterBreak v2.1.0 silently fails to install on 11th gen (C2V2L3) FW 5.15.1 — partial install (fbink dropped, no winterbreak.log / MNTUS_EXEC / pubdevkey01.pem)

### Device
- Model: Kindle 11th gen 2022, MODEL NO. C2V2L3
- Firmware: 5.15.1 (388930 042), confirmed via `/mnt/us/system/version.txt`
- Color/storage: Denim, 16 GB
- Registered to Amazon account
- Wi-Fi network saved and reachable
- Free space: 70 MB (within the 50–90 MB the wiki asks for)

### What I did, following the wiki step by step

1. Airplane Mode ON on Kindle, then reboot.
2. Downloaded `WinterBreak.tar.gz` from the v2.1.0 release (`https://github.com/KindleModding/WinterBreak/releases/tag/v2.1.0`).
3. SHA256: `dc04fff5fcb685834cba9f9e95d4818b473d4100b2d40b8bb7c598ad09eb850d` (matches the GitHub asset).
4. Extracted on Mac, copied `mesquito/`, `apps/`, and `.active_content_sandbox/` (merged) to the Kindle root.
5. Ejected the Kindle, opened the Kindle Store (cart icon) on the Kindle, said Yes to turning off Airplane Mode, Mesquito opened.
6. Tapped the WinterBreak icon.

### First attempt: "UNKNOWN MANIFEST FOUND"

Mesquito's "Toggle log" button revealed the actual error:

```
Mesquito - v0.3.1
Theme loaded
file:///mnt/us/mesquito/themes/com.mesquito.defaultTheme/default.css
Apps:
{"name":"tech.hackerdude.winterbreak","path":"file:///mnt/us/apps//tech.hackerdude.winterbreak"}
{"name":"._tech.hackerdude.winterbreak","path":"file:///mnt/us/apps//._tech.hackerdude.winterbreak"}
file:///mnt/us/apps//tech.hackerdude.winterbreakmanifest.json
file:///mnt/us/apps//._tech.hackerdude.winterbreakmanifest.json
Obtained manifests
{ ... full WinterBreak manifest.json ... }
<HTML error in Spanish: "Ha surgido un problema al cargar esta página">
UNKNOWN MANIFEST FOUND.
```

**Root cause of the first attempt was the macOS AppleDouble `._*` metadata files** that `cp -R` created on the FAT32 Kindle. Mesquito picked up `._tech.hackerdude.winterbreak` as a second app, tried to load its (non-existent) `manifest.json`, and failed.

I deleted the `._*` files I had introduced (in `apps/`, `mesquito/`, and the root `._mesquito`/`._apps`/`._.active_content_sandbox`), left the system-original `._driveinfo.calibre` / `._metadata.calibre` / `._amazon-cover-bug` alone. After that, `apps/tech.hackerdude.winterbreak/` was the only app entry and `mesquito/` had no `._*` files.

### Second attempt: Mesquito loaded WinterBreak, app showed "Jailbreaking - Please Wait..."

After cleaning, opening the Kindle Store brought up Mesquito with the WinterBreak app correctly. Tapping it showed the standard splash (WinterBreak 2.1.0 + Asimov quote + "Jailbreaking - Please Wait..."). The Kindle sat on that screen for about **34 minutes** before returning to the home screen on its own (with the "JAILBROKEN" carousel item present, Airplane Mode apparently re-enabled based on the status bar icon).

### What the filesystem looks like after the second attempt

Files that the wiki / older guides say should be present, **but are NOT**:
- `/mnt/us/winterbreak.log` — missing
- `/mnt/us/MNTUS_EXEC` — missing
- `/mnt/us/etc/uks/pubdevkey01.pem` — missing

Files that **were created** (and were NOT in my pre-jailbreak backup of `/mnt/us/`):
- `/mnt/us/libkh/` — new directory
- `/mnt/us/libkh/bin/fbink` — ELF 32-bit ARM EABI5 executable, ~1.38 MB, modified Jul 2 01:13 2026 (Kindle's local time, ~few minutes before the Kindle returned to the home screen)

`fbink` is the E-Ink framebuffer helper that WinterBreak / KOReader ship. The fact that it was dropped into `/mnt/us/libkh/bin/` strongly suggests that the `jb.sh` payload **started** executing but did not finish.

### Notes from inspecting the v2.1.0 tarball

`apps/tech.hackerdude.winterbreak/dialoger.html` does this:
```js
nativeBridge.accessHasharrayProperty("com.lab126.transfer", "request_upload", {
    url: "http://127.0.0.1",
    source_command: "sh -c 'curl -L https://kindlemodding.org/jb.sh | JB_HEADER=\"Winterbreak Jailbreak\" sh'",
    unique_id: "winterbreak",
    netid: 1,
    priority: 50,
    ...
});
```

So v2.1.0 fetches and runs `jb.sh` from kindlemodding.org. The "winterbreak.log" / "MNTUS_EXEC" / "pubdevkey01.pem" the wiki references would normally be written by that `jb.sh`. If the curl pipe was cut, the log would never be created — which matches what I see.

### Likely failure modes (in order of probability)

1. `curl | sh` was interrupted (timeout, Amazon proxy block, server blip, or `netid: 1` was not honored) and `jb.sh` was killed before the log was written. But `fbink` was somehow already pulled in by an earlier part of the same `jb.sh` that did complete.
2. `jb.sh` has a step that silently exits on the 5.15.1 / C2V2L3 combination — and the user has no UI feedback that anything went wrong. The Kindle just returns to the home after the splash has been on screen for an arbitrary time.
3. Related to issue #57 ("Migrate to modern jb.sh"): v2.1.0 is partway through a migration away from the Mesquito-based flow. The drop of `fbink` into `/mnt/us/libkh/bin/` (instead of the old `usr/bin/fbink` location used by Mesquito-style jailbreaks) suggests the new layout is being installed but the dev-key / MNTUS_EXEC / log writes were not migrated yet, leaving the install half-done and effectively non-functional.

### What I expected

I expected the standard 30-second "ready to install the hotfix" message from the wiki, then Airplane Mode re-enabled and KUAL installable. Instead I got an indefinite wait and a partially-installed filesystem with no way to tell from the UI whether the install succeeded.

### What I'd like from maintainers

- Confirmation that v2.1.0 on 5.15.1 / C2V2L3 is supposed to land the three "old style" artefacts (`winterbreak.log`, `MNTUS_EXEC`, `pubdevkey01.pem`), or — if v2.1.0 is mid-migration — what the new evidence files are so I can tell if the install actually succeeded.
- The new expected post-install filesystem state (which files / symlinks / MNTUS_* flags does a healthy v2.1.0 install produce?). My `/mnt/us/libkh/bin/fbink` exists but I'm not sure if it's a completed install or a half-state.
- Any logs I can pull off the Kindle to diagnose the cut-off `curl | sh`. I'm happy to attach anything from `/var/log/` or wherever the transfer manager writes its traces, if you tell me where to look.
- Whether the issue is the `netid: 1` not forcing Wi-Fi (the inline comment in `dialoger.html` already admits "I don't even know if this is the right key I sure HOPE it is") and what the correct value is for the C2V2L3.

### Related

- Issue #46 (LClarkeW, Sep 2025, PW4 5.16.10.0.1) — same symptom from the user side: "can never generate the requisite cache directory in step 6. I doubt it's space limited". (In my case the LocalStorage cache was not the problem — the `._*` pollution was. But the silent-failure end state looks similar from the outside.)
- Issue #50 (mullermn, Oct 2025) — "Kindle never reboots on install?" — also the "Kindle returns to home on its own" pattern.
- Issue #57 (ThatHackerDudeFromCyberspace, Apr 2026) — "Migrate to modern jb.sh" — looks like v2.1.0 is the in-progress migration. The `/mnt/us/libkh/` layout on my device after this install is consistent with a partial migration landing.


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WinterBreak v2.1.0 silently fails to install on 11th gen (C2V2L3) FW 5.15.1 — partial install (fbink dropped, no winterbreak.log / MNTUS_EXEC / pubdevkey01.pem) #61