The blog post explores methods to extract content from an LCP-protected ePub file, primarily for archiving or personal use. It details the challenges posed by LCP's encryption and license validation, and walks through a technical process involving inspecting the ePub's structure, locating the encrypted content, and ultimately decrypting it using the user's own credentials and a modified version of Adobe's Digital Editions library. The author emphasizes this is for educational purposes only and discourages any copyright infringement. While acknowledging potential legal and ethical concerns, the post frames the process as a way to reclaim control over purchased digital content and ensure future accessibility.
A new jailbreak called "WinterBreak" has been released, exploiting a vulnerability present in all currently supported Kindle e-readers. This jailbreak allows users to install custom firmware and software, opening up possibilities like alternative ebook stores, custom fonts, and other enhancements not officially supported by Amazon. The exploit is reliable and relatively easy to execute, requiring only a specially crafted MOBI file to be sideloaded onto the device. This marks a significant development in the Kindle modding community, as previous jailbreaks were often device-specific and quickly patched by Amazon. Users are encouraged to update to the latest Kindle firmware before applying the jailbreak, as WinterBreak supports all current versions.
Hacker News users discuss the implications of a new Kindle jailbreak, primarily focusing on its potential benefits for accessibility and user control. Some express excitement about features like custom fonts, improved PDF handling, and removing Amazon's advertisements. Others caution about potential downsides, such as voiding the warranty and the possibility of bricking the device. A few users share their past experiences with jailbreaking Kindles, mentioning the benefits they've enjoyed, while others question the long-term practicality and the risk versus reward, especially given the relatively low cost of newer Kindles. Several commenters express concern about Amazon's potential response and the future of jailbreaking Kindles.
The author experienced system hangs on wake-up with their AMD GPU on Linux. They traced the issue to the AMDGPU driver's handling of the PCIe link and power states during suspend and resume. Specifically, the driver was prematurely powering off the GPU before the system had fully suspended, leading to a deadlock. By patching the driver to ensure the GPU remained powered on until the system was fully asleep, and then properly re-initializing it upon waking, they resolved the hanging issue. This fix has since been incorporated upstream into the official Linux kernel.
Commenters on Hacker News largely praised the author's work in debugging and fixing the AMD GPU sleep/wake hang issue. Several expressed having experienced this frustrating problem themselves, highlighting the real-world impact of the fix. Some discussed the complexities of debugging kernel issues and driver interactions, commending the author's persistence and systematic approach. A few commenters also inquired about specific configurations and potential remaining edge cases, while others offered additional technical insights and potential avenues for further improvement or investigation, such as exploring runtime power management. The overall sentiment reflects appreciation for the author's contribution to improving the Linux AMD GPU experience.
Summary of Comments ( 3 )
https://news.ycombinator.com/item?id=43378627
HN commenters generally express skepticism towards the robustness of LCP "protection," viewing it as a minor speedbump rather than a genuine barrier. Several point out that determined users can always access content through methods like disabling JavaScript or using developer tools. One commenter mentions DeDRM tools as an existing solution for bypassing such restrictions, while others suggest that the real protection lies in social pressure and legal consequences, not technical measures. The feasibility of converting ePubs to PDF and then extracting text is also discussed. Overall, the sentiment is that DRM ultimately harms accessibility and legitimate users more than pirates.
The Hacker News post "Extracting content from an LCP "protected" ePub" has generated several comments discussing the effectiveness and ethics of LCP (Limited Content Protection) for ebooks.
One commenter points out the inherent weakness of DRM, stating that if a device can render the content, it can be captured. They argue that DRM only inconveniences legitimate users while dedicated pirates will always find a way around it. This comment highlights the common sentiment that DRM is a futile effort in the long run.
Another commenter dives into the technicalities, explaining that LCP isn't designed to prevent copying, but rather to associate a specific decryption key with a user or device. They describe how LCP uses a server to deliver keys, and how the described method intercepts this communication to obtain the key. This clarifies the actual function of LCP and how the exploit bypasses it.
A further comment expands on the limitations of LCP, mentioning that it doesn't protect against screen scraping or even simply printing to PDF. This emphasizes the vulnerability of the protection scheme and how easily it can be circumvented by relatively simple methods.
The discussion also touches on the legal aspects, with one commenter noting that circumventing DRM, even poorly implemented DRM like LCP, might still be illegal depending on jurisdiction. This provides a counterpoint to the purely technical discussion and highlights the legal ramifications of such actions.
Another commenter criticizes Adobe's implementation of LCP, calling it "pathetic" and suggesting that it provides a false sense of security to publishers. They express frustration with the apparent lack of effort in implementing a robust protection scheme.
Finally, some comments focus on the underlying issue of control versus access. One user argues that publishers fear losing control over their content, while another contends that what publishers really want is the ability to track and control access to the content. This highlights a philosophical difference in approaches to digital content distribution.
In summary, the comments express a general skepticism towards LCP's effectiveness as a DRM solution. They highlight the inherent limitations of DRM, discuss the technical aspects of the exploit, and touch upon the legal and philosophical implications of digital content protection. Several commenters express frustration with the perceived weakness of LCP and the seeming futility of DRM in general.