There is no need to format because we write complete disk image to a USB stick/SD card. Any data on a device is overwritten.
But you can use SDFormatter tool to remove both partitions and create only one big one when you don't need this device for libreelec.
You missed the fact that official images doesn't include all what is described in this thread. You need special image build by yourself or some other good guy. Ask in thread for a new image.
I don't think there was any changes in this area. Which touchscreen is this?
Evtest addon should be available as part of system-tools addon.
The question was about why Libreelec removed it?
Because libreelec extracts skin from kodi sources and use only Estuary.
I assume this skin is included only with Kodi itself. Because libreelec remove it then can't be installed from repository.
Did you tried to install my zip file manualy?
Update: Just tested this zip and skin works.
At the end I did managed to get arc function in work. Will try to reproduce your issue and if I can repeat that then I will also tried to fix it. If not it will stay as is.
Only Estuary skin is included by default.
You can try this Estouchy: kodi-theme-Estouchy-17.0-beta1-81d5d26.zip
Sadly I can't setup ARC with my Samsung TV UE40JU7090 and AV receiver Onkyo TX-SR508. I think I had this already running when I got TV few months back and don't understand why now doesn't work anymore. Maybe some TV upgrade.
Meaning I can't reproduce this issue to try to fix it... 
Any tip welcome.
Edit: Having it working yesterday and today doesn't work anymore.
But did it ask you for a password when launch app?
Can you click the icon while keeping Ctrl button pressed to open it?
If this doesn't work (you still get Not enough space on /dev/disk2 [?? MB < 548.0 MB]
- notice the ??) then please try LibreELEC.USB-SD.Creator.macOS-test1.dmg with and without Ctrl button pressed.
Can you describe in detail how you have all 3 devices hooked up? Cuboxi to TV on one hdmi and also soundbar to tv on another hdmi (with arc)?
I will play a little over weekend and see if I can reproduce the issue. But I don't have any soundbar - only Onkyo AV receiver. And in my tests it was turned off and cuboxi was connected directly to tv.
There are 2 numbers with this text mesage - can you post it here?
And also output of command in console terminal:
diskutil info /dev/your_sd_cardAnd did you run it with sudo or you got some error when app was started?
The only problem is who will analyze them and fix the issues 
Yes, just update fully working version.
Calibration file is /storage/.config/ts/pointercal. You can save whole /storage/.config/ts folder in case you need to make fresh install.
With this kernel everything is fine.
Any idea to what this is related? Can we fix this
Use what works for you. As you can see imx6 project doesn't have any real dev to fix most issues.
I have been switching between the kernels with the .tar files, is that okay or can it cause problems?
Yes, it is okay.
Can you try this image: LibreELEC-imx6.arm-7.90.005-sr-3.14.img.gz
For me with Samsung TV UE40JU7090 still working as it should. Maybe it is your TV to blame
Is there any chance to compile php5-libsmbclient
I will look as soon I could.
About cec not working on 3.14 - this are my cec seetings
I can manually turn off TV or leave screensaver kick in. After powering Tv back on CEC is still working.