If you still have Android then you may be able to use Reboot to LibreELEC app or type ‘reboot update’ from console or terminal app without having to resort to USB Burning Tool, we are just following his mantra that a full reinstall is required.
An alternative to the usb burning tool, is the card maker. This seems to me to be an easier method. Although, it might not work.
Thanks everyone. I have UBT’d stock back onto my box and I am able to boot CE. I am using the 4g dbt ffrom the the included folder. My own “dd if=/dev/dtb” doesn;t work, just giving me a black screen. I get the same black screen when trying to use the included 4g_1gig dtb (excuse my naming convention, I am just saying I have 100 mbps rather than 1gig LAN)
I am ssh’d into my box right now and currently downloading the emuelec 3.4 tar into my .update folder 
Edit to add - Emuelec now doesn’t boot. It looks like I will have to reflash and just use their addon instead.
Tahnks for an amazing project though. I have been using CE on my Nexbox A1 S912 box for over two years now and find it really stable and nippy.
I use UTB rather than sdcard maker as I find it is quicker than having to mess about with slooooooow writing times to an SD card.
edit2add2
Emuelec works when flashing its own img to sdcard, I still have to use the 100mbps dtb.img though but It’s an acceptaable trade-off. Now, to flash CE again as the missus is complaining about the lack of kodi in the lounge