Porting linux applications for Kindle PW5

[kindler]

Hi,

I have a jailbroken Kindle Paperwhite 5, and I require access to the BLE stack in order to use some commands. My goal is to find a way to build and install packages like BlueZ to get access to hciconfig, hcitool, and bluetoothctl.

Although there are resources on creating development environment VMs for Kindles, I would appreciate receiving any tips or advice that you may have before investing days of time and effort in them to port on my SoC.

Additionally, I noticed that "devcap-get-feature -a bluetooth" returns a value of "1", indicating that Bluetooth functionality is available. However, I do not have access to Bluetooth in the menu. How can I enable the Bluetooth feature on the UI so that I can connect to Bluetooth audio devices?


Thanks

[shamanNS]

You must register / login the device to an Amazon account only then it will show all the options in Settings and also that BT on/off toggle.

[kindler]

Oh, good point, thanks

What about porting/building C applications for Kindle kernel, or adding to busybox.

[NiLuJe]

For CLI or systems stuff, just cross-compile to the right target and you're done?

(i.e., https://github.com/koreader/koxtoolchain [Use the binaries right now, the latest gnu make release breaks the glibc build. Updating those TCs, which will also fix this issue, is at the top of my TODO list]).

[katadelos]

Originally Posted by kindler

Hi,
I require access to the BLE stack in order to use some commands. My goal is to find a way to build and install packages like BlueZ to get access to hciconfig, hcitool, and bluetoothctl.

Minor point of distinction - BlueZ is an entire BT stack that happens to include tools to interact with that stack.

If things are similar to the other Kindles with Bluetooth, the BT stack on the device is an entirely different one provided by the chip vendor and is very limited /essentially a pile of shit. You'd need to swap it out with BlueZ entirely for the other tools to work IIRC.

Originally Posted by kindler

Although there are resources on creating development environment VMs for Kindles, I would appreciate receiving any tips or advice that you may have before investing days of time and effort in them to port on my SoC.

Weeks is probably more accurate if not more. First step is probably to stop thinking of it as a Kindle and start thinking of it more generically as a small ARM board running Linux - you'll find a lot more information and resources this way.

This book is a great starting point: https://www.oreilly.com/library/view...ux/059600222X/

As for actually building stuff, the easiest way would be to do everything within buildroot to make compiling dependencies etc slightly less painful.

[NiLuJe]

Yup, buildroot will probably save you a good amount of hair-pulling, and has the added benefit of being (fairly) straight-forward, given the huge complexity of the task at hand .

[DNSB]

TWIMC: perhaps this thread should be moved to the Kindle Developer's Corner?

[NiLuJe]

@DNSB: Oops, indeed, missed that fact .

Done.

[kindler]

Originally Posted by NiLuJe

For CLI or systems stuff, just cross-compile to the right target and you're done?

(i.e., https://github.com/koreader/koxtoolchain [Use the binaries right now, the latest gnu make release breaks the glibc build. Updating those TCs, which will also fix this issue, is at the top of my TODO list]).

Thank you for your help. After conducting some tests with the koxtoolchain, I cooked a new toolchain using crosstool-NG. This new toolchain worked well with a simple program that printed "hello world"!

I then proceeded to build Bluez along with its dependencies such as dbus, readline, and glib. Finally, I was able to obtain the necessary binaries and libraries.

While investigating kernel compatibility and ensuring the Kindle was enabled for Bluetooth in the UI, I, unfortunately, made a mistake. This resulted in an auto-upgrade and I lost my jailbreak. I had previously looked into preventing auto-upgrades based on information from various threads, but I mistakenly assumed that my workaround was successful. However, it turned out that device registration triggered the upgrade process. now it upgraded to 5.15.1.1

[dhdurgee]

Had you done the JB prior to the update? You might be able to apply the latest hotfix and recover from this.

Dave

[kindler]

Yes, it was jailbroken on 5.14.2 for a while and after registering the device it just got a new OTA upgrade.
Which patch exactly? I don't have SSH access also unlike here.

[kindler]

I tried this hotfix and it was rejected as an invalid update file.

K5 JailBreak Hotfix | JailBreak-1.16.N-FW-5.x-hotfix.zip | 2023-Jan-04 23:53:15 | 150.2K | 165a5e72bd9bb0de099459b96339f3cf | JB Hotfix

[dhdurgee]

Originally Posted by kindler

I tried this hotfix and it was rejected as an invalid update file.

K5 JailBreak Hotfix | JailBreak-1.16.N-FW-5.x-hotfix.zip | 2023-Jan-04 23:53:15 | 150.2K | 165a5e72bd9bb0de099459b96339f3cf | JB Hotfix

You might want to check with NiLuJe as I seem to recall that the latest firmware update required an update to the hotfix.

Dave

[NiLuJe]

I'm not in a position to check and/or rebuild anything at the moment; but, as a rule, if the snapshot's thread timestamp at the bottom predates a FW release date, the hotfix will obviously not work .

On the upside, you don't need to run the hotfix at all, just reboot a couple of times.

[dhdurgee]

Originally Posted by NiLuJe

I'm not in a position to check and/or rebuild anything at the moment; but, as a rule, if the snapshot's thread timestamp at the bottom predates a FW release date, the hotfix will obviously not work .

On the upside, you don't need to run the hotfix at all, just reboot a couple of times.

My recollection is that the latest firmware release relocated the keystore and as such would require changes to the code to recover from an update of the firmware to that release. Unfortunately I don't recall what level incorporated that change, so I am unsure if he is being bit by it or not. I hope that you are correct and that the bridge code can recover things for him with a few reboots.

Dave

PS: from the Open Sesame Thread:

WARNING: FW >= 5.15.1.1 INTRODUCED A BREAKING CHANGE. DO NOT UPDATE!