First I tested the original firmware that the Xteink X4 comes with and after that I have been using the CrossPoint Reader v1.2.0 firmware and now I am using the CrossPoint Reader ++ Firmware fork, and now the KOReader SYnc works much better!
CrossPoint Reader ++: Enhancing the Xteink X4
E-Paper Experience
Introduction to CrossPoint Reader ++
CrossPoint Reader ++ is a specialized firmware fork optimized for the Xteink X4 e-paper display reader. Built upon the foundational work of Dave Allie and the broader community, this project addresses the specific technical limitations of the original repository. As a "feature-forward" fork, it prioritizes the rapid integration of community-driven enhancements and low-level stability fixes that have otherwise stalled in the upstream development pipeline.
The Motivation: Why This Fork Exists
The creation of the CrossPoint Reader ++ branch by developer jpirnay was a response to the stagnation of the main repository. In the world of open-source firmware, upstream projects often fall into a "least common denominator" trap, where niche but vital technical improvements rot in the Pull Request (PR) queue due to a lack of clear governance.
This fork exists to bypass these upstream synchronization bottlenecks and address several critical pain points:
- CSS Parsing Regressions: Persistent rendering issues in the official branch often break e-book layouts. This fork implements rigorous fixes to ensure CSS compliance and visual fidelity.
- Heap Management & Stability: Users have long faced Out-of-Memory (OOM) errors during secure handshakes. By resolving the HTTPS TLS OOM issues, this branch provides the stability required for modern wireless workflows.
- Development Velocity: By operating independently, this branch can integrate "good ideas" and community fixes at a pace the official repository currently cannot match.
Key Improvements and New Features
CrossPoint Reader ++ introduces a suite of "under-the-hood" performance optimizations alongside visible toolsets designed for the serious reader:
- Robust KOReader Synchronization: Beyond basic progress syncing, this fork includes a specific HTTPS TLS OOM fix. On the low-power hardware of the Xteink X4, efficient heap management during the TLS handshake is a major stability milestone for wireless syncing.
- Typography & Rendering: Extensive fixes for CSS rendering issues ensure consistent text presentation. This includes sophisticated typography adjustments such as differential rounding for consistent inter-glyph spacing, a feature essential for high-quality e-ink legibility.
- Advanced Sleep Screen Support: Users can now utilize information overlays and transparent images over the current reading screen, allowing for at-a-glance data without losing place in a book.
- Accessibility & Utility:
- Reading Ruler: A dedicated accessibility tool to assist with line tracking and focus.
- Weather and Clock Panels: Integrated system-level panels for environmental awareness.
- Book Information Screen: Deep metadata visibility for the active library item.
- Release v1.31 - "Font Darkness": The latest release focuses on the "reading experience" by introducing Font Darkness settings, allowing users to tune the contrast of the e-paper display to their specific lighting conditions and visual needs.
Comparing E-Reader Firmware Flavors
Selecting the right firmware involves balancing feature sets against hardware support. The following table compares the current "flavors" available for the Xteink X4 as of April 2026:
Reader Name | Visual Appeal | Core Functionality | Supported Formats | Pros | Cons |
CrossPoint ++ (This Fork) | Okay | Calibre Wireless; KOReader sync; Wi-Fi transfer; Clock/Weather | EPUB, XTC, TXT | Faster integration of fixes and features | Small team; no custom fonts, CJK, or Bluetooth |
Stock | Okay | Basic Reader | XTC, EPUB, TXT | Frequent official updates; Supports Custom Fonts/CJK/Bluetooth | Significant CSS rendering regressions |
CrossPoint | Okay | Calibre Wireless; Limited KOReader sync | EPUB, XTC, TXT | Largest community support | "Least common denominator" feature set |
CrossPet | Excellent | Virtual pet motivator; mini-games | EPUB, TXT | Playful interface; many additional apps | High battery drain; perceived as "bloaty" |
Papyrix | Minimalist | Calibre Wireless; exFAT support | EPUB, FB2, MD, TXT | Highly innovative feature ideas | Small development team |
Inx / vCodex | Nice | Reading statistics | EPUB, XTC, TXT | Strong visual appeal; detailed stats | Small development team |
PlusPoint | Okay | Experimental JS App support | EPUB, TXT, JS | Custom JavaScript app support; improved RTC | Based on legacy codebase; small team |
Technical Snapshot and Project Status
Technically, the project is a high-performance implementation grounded in low-level systems programming. The codebase is comprised of approximately 81% C and 16% C++, utilizing smart pointers and a modular ParsedText class architecture to improve memory safety.
Current Activity Level: The project is under active development. Recent commits (as of April 8th, 2026) have addressed critical issues such as OTA (Over-the-Air) update redirects and wild pointer crashes in JPEGDEC handling. The rapid turnaround on these regressions demonstrates the fork's commitment to a stable, "daily-driver" ready firmware.
Conclusion and Availability
For Xteink X4 users who find the official development cycle too conservative or the rendering issues too intrusive, CrossPoint Reader ++ offers a performance-oriented alternative. By focusing on the fundamentals—typography, synchronization stability, and functional utilities—it transforms the X4 into a more capable, professional-grade reading device.
The project is released under the MIT License. For the full source code, installation instructions, and the comprehensive USER_GUIDE.md, please visit the official GitHub repository.
Find the fork here:
https://github.com/jpirnay/crosspoint-reader
Flash it here:
Watch video here:
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