Comment by jsheard
10 days ago
If you want a cheap rooted eReader I think you're better off getting a Kobo instead, they don't officially support rooting but AFAICT they make basically no effort to prevent it.
10 days ago
If you want a cheap rooted eReader I think you're better off getting a Kobo instead, they don't officially support rooting but AFAICT they make basically no effort to prevent it.
The latest Kobos use MediaTek SoCs with locked bootloaders. The Kobo Clara BW's MT8113, for example. As far as I know, one of the early bootloaders it, BL1, refuses to execute the next bootloader (BL2) unless its signature is valid. We can get the device into a mode where BL1 waits for upload of a BL2 via USB using an exploit called Kamakiri, but in public there is neither an exploit to get BL1 to boot an arbitrary BL2, nor an authorized BL2 image to upload. See here: https://github.com/bkerler/mtkclient/issues/1332
Kobo devices have root exposed but don't let users boot their own kernels (and the kernel they ship was not compiled with kexec either).
I really don't know the reason so many devices these days don't have an unlock method. It seems predatory. Who knows where in the chain this happens... maybe it's Kobo, or maybe MediaTek won't sell you their SoCs for mass-market devices unless you lock them.
Can you just access /dev/mem or load a kernel module? Is there a SELinux policy stopping that?
If you can do either of those, it should be trivial to get kexec working by just loading it as a module.
As far as I know, yes, it's possible. No SELinux. Kernel is a branch from 4.9.something pretty far off mainline with a few proprietary binary blob modules. As far as I know the real impediment here is lack of demand.
According to the github issue it seems to be a simple checksum step, not a true signature verification? If so there is no locked bootloader in any real sense.
If the real impediment is lack of demand or low-level development effort for any given device, that's in principle a solvable issue once projects like pmOS and Mobian choose to focus on some reasonably-available hackable hardware and bring it up to true daily driver state.
mtkclient does not seem to correctly interpret the usb output of the device past some part of the early boot process. Really, any of those messages formatted by mtkclient are unfaithful to the intended meaning. So yes maybe it is "just a checksum step" or maybe something else entirely. Last year I collected some UART logs on the device during bootup in a zip here:
https://github.com/bkerler/mtkclient/issues/1289
The details in this comment are messed up and shouldn't be taken as authoritative.
- Getting the device's BL1/BROM into download mode (where it waits for an upload of a Preloader/BL2 from outside), for these devices itself does not involve exploits. Kamakiri is an exploit in the upload process that gives an execution point at that stage.
- The BROM on Kobos (at least the old ones, P365's) don't have security enabled as far as I know. (Unless somehow they are lying to us when we ask, which there is no evidence of). They only do some integrity checks (header magic #s, checksums).
- Security on Kobos happens down the chain, starting at the Little Kernel apparently jumped to from the Preloader. I am still learning about the Clara BW's boot process.
Older Kobos sound ok though?
+1 to a Kobo, they cheaper and better than Kindles, with full Calibre support (https://github.com/kovidgoyal/calibre - OSS which has been in development for ~20 years!).
The way you install additional software is literally just moving files into folders whilst its plugged into your computer. I'm sure it could handle Tailscale.
I agree with your sentiment that the Kobo is better than the Kindle from an... ethical standpoint, if you have the money for one. However, it is worth noting that Kindles will always be cheaper than Kobo devices [0] due to economies of scale and lockscreen advertisements (removable with jailbreaking). From a pure cost perspective, and assuming the user is technically-minded enough to accomplish the jailbreak, the Kindle is likely always [1] a better deal.
[0] as of today, 12/8/25, the "base model" Kindle 11th Generation is priced at $109.99 USD, and the respective Kobo Clara BW is $139.99 USD.
[1] I say "likely always" to cover my bases. To my knowledge Calibre supports Kindle, just not as well as Kobo. That said I have found that the KOreader app is more than powerful enough for my use case (reading my own epubs, using dictionaries, etc.)
That doesn't always hold, if you want color e-ink then Kobo is currently the cheaper option.
Kindle Colorsoft (7" 16GB) - $250
Kindle Colorsoft (7" 32GB) - $280
Kobo Clara Color (6" 16GB) - $160
Kobo Libra Color (7" 32GB) - $230
The Libra also supports a stylus (sold separately) while the Colorsoft doesn't, that's reserved for the much bigger and pricier Kindle Scribe.
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Plus the kindles will get decent discounts on prime day, black friday and such.
Where do I get DRM-free ebooks to put on a Kobo? I don't support breaking DRM. So I'm using a Kindle because it has the best access to and integration with almost any book I want.
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Also consider koreader instead of the stock reader app.
I kinda love that buried in the koreader menu somewhere is an option that drops me at a linux shell. I have no use really for this feature, but i like it. Good for those times you absolutely have to crank out some awk on the plane or whatever. :)
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I use the Calibre support, but did not know you could install additional software that easily!
Most (?) Kobos can run libby so you can get ebooks from your library.
Kobo is great. I use Plato and KOReader on mine. They worked better than the original reader software for reading manga.
Same with the Barnes and Noble Nooks. I've never rooted one, but via ADB one can install a launcher and most Android applications run. I've used four generations of Nooks to run AnkiDroid.
Just beware to check what version of Android the Nook is using before you buy, and what your app needs.
Android on an e-reader unlocks so much potential. I've owned four or five Kindles over the years but recently switched to an Onyx Boox page 7" as my main e-reader. Expensive (relative to Kindles) but runs full Android 11 and has physical page turn buttons. I use an app called BookFusion to sync my library including reading position across all platforms. Battery life isn't Kindle grade but I can get by charging once a week which is a good enough tradeoff for the convenience of being able to run Android apps.
The only (tiny) issue I've had with Tailscale on Kobo has been that the tailscale daemon prevents me from using the Kobo in Mass Storage Mode while it's active, so I have to disable/quit KOReader to be able to plug it in again, which is admittedly not frequently warranted anyways.
I used to like my Kobo a lot but recently it's got some pretty severe unreliability issues, usually around reading non-Kobo epubs and PDFs. Like, if I open of those files, the device usually crashes and when it recovers after a reboot, the file disappears.
I was more after a eink display in a shape that is cheaper than new boards for a DIY project