[Rrrr]

I booted with CRTL-D then CTRL+ALT+F2
Downloading the E-Z script was not easy and required several tries:

curl: failed to connect to mrchromebox. tech port 443: Connection timed out

In the script I selected 2 for dual boot update.

After repartitioning and Updating bootloader, I get this:

Error: failed to download syslinux: check your internet connection and try again.

My internet connection seems fine. Is this the LAN bug or is your server offline?

I am unsure if I can reboot now and will have access again or if the repartitioning has damaged the boot process.

Info:
* ifconfig gives me the IP;
* SSH to IP fails. 

  
my server isn't showing any issues, can't really control the vast swath of internet between it and everyone else though.

the LAN issue affects Linux kernel 4.19+, so not ChromeOS.

rebooting would leave you in the same state you are now, You simply need to reinstall LE until it works   

Thank you. I tried many times...then thought it would not hurt to factory reset the system which I also failed with (see below).

Chromebook Recovery Utility (CRU)
I got into more trouble: CRU does not manage to finish installing the image on the memory device:
a) on 2 Windows 10 devices the write operation keeps looping. I also tried safe boot with networking, etc;
b) on the Chromebox: Getting "Unable to unzip file. Please try again.".

===CORRECTION OF THE ABOVE===
a) the 'looping' on W10 machines is not what I thought. The tool is just writing a number of partitions to the USB flash drive.
b) my chromebox only has 1.1Gb available storage and could therefore not finish creating the image to the USB flash drive. In this case, use another machine.
===END OF CORRECTION=======

Recovery image
Following the instructions here, I downloaded the image for my CN60 (panther-f5u-a4a-a5c) from My Chrome Home.
After unzipping with 7zip I wrote the .bin image with chromeosimagecreatorV2.exe directly to my memory devices (after erasing the recovery media first).

===CORRECTION OF THE ABOVE===
My experience is that this .bin image  is not accepted (anymore) by Chromeos.
You are better off using the CRU (above)
===END OF CORRECTION=======

Loading ChromeOS
With 2 different USB memory keys and an SD card I did not manage to have CN60 ChromeOs recognise there is an O/S on the memory device upon insertion.

===CORRECTION OF THE ABOVE===
I now succeeded with three 8GB USB sticks: Sandisk Cruzer, Kingston and unbranded. 
The trick is to wait until the CRU tool is completely done wiriting each partition.
===END OF CORRECTION=======

The next day back to EZ script
As per your reply, this time I managed to download LibreElec after selecting 2 for dual boot update:
LibreElec download complete: installing...
cp: error writing '/tmp/System/SYSTEM': No space left on device.

Please can you confirm what this means? My understanding is my partitions may be too small so I have to:
1. Perform a factory reset (I'll have to try again, any tips?);
2. Reinstall EZ script and run it again (is there another way?).