After much trial and error, false starts and...so much log reading, I managed to get a keyboard over Bluetooth classic (not BLE) working on my PW5/PW6 running jailbroken 5.18. (Older versions may also work, I just don't have any devices to test on.)
This definitely requires a jailbroken device and some kinda dangerous operations.
Enabling Bluetooth HID devices
This requires a small udev rule to keep things working after reboots, reconnects, or btmanagerd crashes ;)
The Kindle comes with a version of the X server (v1.8.2, from 2010) that requires udev 148 or newer to support "hot plugged" input devices, because the X server looks for certain properties on the devices that older versions don't set. Unfortunately, the Kindle firmware ships udev 146, so we have to do that part manually. Since Bluetooth keyboards will basically always be hot plugged (you don't want to restart the X server every time it connects), this is an important step.
Create a small shell script (e.g. /usr/local/bin/dev_is_keyboard.sh, and don't forget to chmod +x) that detects whether an attached device is capable of keyboard input.
Now, we need a file to run this as part of a udev rule, and fix up some file permissions. Create one, like /etc/udev/rules.d/99-bt-keyboard.rules:
The first rule is necessary as restarts of btmanagerd seem to reset it to being owned by root. The second one runs the script and adds its output to the properties of the device.
Run udevadm control --reload-rules once this is in place.
Pairing a device
The ace_bt_cli tool can be used to manipulate the Bluetooth (classic and BLE) system.
Check if bluetooth is enabled
Run radiostate; you should see ACEBTCLI getRadioState() state:1 status:0.
If it's not enabled, run enable.
Run help to see all the options, but we're mostly just interested in pair here.
Finding your Bluetooth address
You can try classic scan here, but it also filters out non-audio devices. You'll need to know the Bluetooth address of your keyboard. (On macOS, you can find it in the Bluetooth settings: option-click on the icon for your keyboard in the device list. Alternately, install blueutil and run blueutil inquiry. I'm not sure how to do this on Windows or Linux, sorry.)
Pairing
Once you have the address, pair it -- the address must be colon separated (or no separator at all):
At this point, if everything went correctly, you should have a connected keyboard that can type in applications like kterm, the built-in browser, etc.
If it didn't work, you'll have some debugging to do.
Debugging
While this is probably a bit more invasive than most would hope, I thought I'd share what I found and document the debugging steps for any future determined souls :)
This definitely requires a jailbroken device and some kinda dangerous operations.
Enabling Bluetooth HID devices
This requires a small udev rule to keep things working after reboots, reconnects, or btmanagerd crashes ;)
The Kindle comes with a version of the X server (v1.8.2, from 2010) that requires udev 148 or newer to support "hot plugged" input devices, because the X server looks for certain properties on the devices that older versions don't set. Unfortunately, the Kindle firmware ships udev 146, so we have to do that part manually. Since Bluetooth keyboards will basically always be hot plugged (you don't want to restart the X server every time it connects), this is an important step.
Create a small shell script (e.g. /usr/local/bin/dev_is_keyboard.sh, and don't forget to chmod +x) that detects whether an attached device is capable of keyboard input.
Code:
#!/bin/sh
DEVICE=$1
if evtest info $DEVICE | grep -q 'Event type 1 (Key)'; then
if evtest info $DEVICE | grep -q 'Event code 16 (Q)'; then
# Don't set these just because Key is supported -- that will
# detect the touchscreen as a keyboard which breaks the UI
echo ID_INPUT=1
echo ID_INPUT_KEY=1
echo ID_INPUT_KEYBOARD=1
fi
fiCode:
KERNEL=="uhid", MODE="0660", GROUP="bluetooth"
ACTION=="add", SUBSYSTEM=="input", IMPORT+="/usr/local/bin/dev_is_keyboard.sh %N"Run udevadm control --reload-rules once this is in place.
Pairing a device
The ace_bt_cli tool can be used to manipulate the Bluetooth (classic and BLE) system.
Code:
ACEBTCLI BT Client :: start
p_data (size:27) = 1B 00 00 00 00 00 00 00 00 00 00 61 63 65 5F 62
74 5F 63 6C 69 00 00 00 00 00 00
ACEBTCLI BT Client :: opened session with 0x19b9550
>:Run radiostate; you should see ACEBTCLI getRadioState() state:1 status:0.
If it's not enabled, run enable.
Run help to see all the options, but we're mostly just interested in pair here.
Finding your Bluetooth address
You can try classic scan here, but it also filters out non-audio devices. You'll need to know the Bluetooth address of your keyboard. (On macOS, you can find it in the Bluetooth settings: option-click on the icon for your keyboard in the device list. Alternately, install blueutil and run blueutil inquiry. I'm not sure how to do this on Windows or Linux, sorry.)
Pairing
Once you have the address, pair it -- the address must be colon separated (or no separator at all):
Code:
>: pair 19:18:17:16:15:14If it didn't work, you'll have some debugging to do.
Debugging
Spoiler:
While this is probably a bit more invasive than most would hope, I thought I'd share what I found and document the debugging steps for any future determined souls :)
