Connect Rapoo MT750S with Linux (Tested on Manjaro)

 I bought this obvious copy of MX Master 2S in hopes of having the device switching functionality along with a lightweight body because I have a hard time with heavy mice, like MX Master itself. Also, the ergonomics is a killer here.

But I was having a hard time figuring out how to pair it to my Linux machine, Windows 10 was fine. Literally spent hours trying to Google a solution down. Nothing was showing up. The official pages only provide links to Windows Driver and MacOS drivers. The user manual is more of a translation tutorial rather than something useful. Really really hard to read with such small fonts as well.

But fortunately, switching the search term turned up with a russian blog post that had instructions for it. And an undocumented (or hard to find in the documentation) feature is all I needed. So I am going to post that here in order to keep a record and hope someone else does not have the same hard time.

Things to know:

1. The device switcher button on the mouse has a "long press" functionality. It puts the specific responder on so the device tries to connect with that.
2. You need to install 'hcitool" from AUR

Steps:

1. First need to find out the MAC Address of the Bluetooth device. To do that, in your terminal type
   
   

   hcitool scan

2. With your mouse turned on, long press the device switcher button. You will see that the device number blinker slows down and blink with less frequency. This is, according to the manual, when the mouse is trying to connect to a device
3. At this point, the hcitool command should turn up with a MAC Address
4. Now in terminal, type
   

   bluetoothctl

5. Now type
   

   trust <MAC Address>

6. And type
   

   connect <MAC Address>

7. At this point, your mouse should be working already

All credits go to the author of this page: http://thenevertimes.blogspot.com/2019/03/rapoo-mt550-pairing-with-linux-mint-173.html

Keeping a copy of that page here for future reference:

From sunny China came a mouse for the laptop - Rapoo MT550. Excellent ergonomics, power supply from 2xAA batteries promises to be long-lasting, and the most killer feature is work simultaneously with three computers via bluetooth with a simple switch.

Under Windows 10, no problems arose - I turned it on, clicked the "bluetooth scan" on the mouse, Windows found it and that's it.

Under Linux Mint 17.3 Cinnamon - the mouse is visible, but when trying to connect, it is impossible to enter pin code "0000" for this mouse in the pop-up notification. Accordingly, the BT manager has a mouse, but it is indicated that the pairing did not occur. Probably no problem under KDE or other shells.

The solution is that you need to manually pair:

1. Install the packages:

apt-get install bluez-tools
apt-get install bluez-hcidump

The first one swears that it is "untrusted".

2. Execute, on the mouse, press the "bluetooth" button for recognition:

hcitool scan
Scanning ...
6C: 5D: 63: 77: 1D: 1E  RAPOO BT3.

3. In a new terminal window:
sudo hcidump -at
HCI sniffer - Bluetooth packet analyzer ver 2.5

device: hci0 snap_len: 1500 filter: 0xffffffffffffffff

4. We are interested in hci0, execute:

sudo bluez-simple-agent hci0 6C: 5D: 63: 77: 1D: 1E

RequestPinCode (/ org / bluez / 11002 / hci0 / dev_6C_5D_63_77_1D_1E)

Enter PIN Code: 0000

Release

New device (/ org / bluez / 11002 / hci0 / dev_6C_5D_63_77_1D_1E)

It will ask for a pincode, for MT550 - "0000"

5. Making the bluetooth mouse "trusted"

sudo bluez-test-device trusted 6C: 5D: 63: 77: 1D: 1E yes

6. We cling to the mouse:

sudo bluez-test-input connect 6C: 5D: 63: 77: 1D: 1E

You can try to move the mouse - it should be recognized. After rebooting, it was recognized automatically, and in the Bluetooth manager of Mint itself, the mouse is now indicated as paired. 

7. For MT750 / 750S, the connection instructions are the same.

UPDATE for those who have Mint 19 / Ubuntu 18.04:

Although the mouse is detected in the bluetooth manager, it still does not want to connect at point-blank range. Simple-agent and the commands associated with it no longer work
in  bluez-tools .
To connect, enter:
hcitool scan - and hold down the channel selection button (on Rapoo 750S), we see the mouse:
Scanning ...
6C: 5D: 63: 76: AA: 17  RAPOO BT3.0 MS

Next, run the utility:

sudo bluetoothctl 

Shows a bunch of devices in the area, incl. and mouse (for some reason I have different macs and BT versions):

[NEW] Device ED: 8E: 0E: 10: AA: 28 RAPOO BT4.0 MS

[NEW] Device 6C: 5D: 63: 76: AA: 17 RAPOO BT3.0 MS

Then in the console [bluetoothctl]:

help - list of commands

We need to entrust the required MAC and connect:

[RAPOO BT4.0 MS] # trust 6C: 5D: 63: 76: AA: 17

[CHG] Device 6C: 5D: 63: 76: AA: 17 Trusted: yes

Changing 6C: 5D: 63: 76: AA: 17 trust succeeded

[bluetooth] # connect 6C: 5D: 63: 76: AA: 17

Attempting to connect to 6C: 5D: 63: 76: AA: 17

[CHG] Device 6C: 5D: 63: 76: AA: 17 Connected: yes

Connection successful

I can't vouch for the trust / connect sequence - first I tried connect, then trust - the result is negative. After trust - again connect - everything came to life. 

At the time of connect,  you must also keep the channel selection on the 750S.