I switched on this morning and get the HK splash, then the CoreELEC boot screen but nothing further 
I am able to view everything via my MAC so can interact that way. There is a log file of todays date for instance.
But I donât know what to do next. I bought the Odroid fully configured so I wouldnât have to get myself in a mess with installation 
CE installed to eMMC 4Gb / 16 Gb
The one instance that happened since last night and today is Plex. I added a trial plexshare using PlexKodiConnect a couple of days back. Overnight the trial ended - is this anything connected with not being able to boot anymore?
I would have hit the reset switch as Iâm so upset at losing the system but I donât think the Odroid has one?
For starters, cut the power, disconnect the network and try again.
Yep sorry I should have added what Iâve tried so far.
Full disconnect, different HDMI ports as well as cables. Have taken my soundbar out the equation and connected straight to TV.
HmmâŚ, what I would try in your case is make a fresh installation on uSD card, just to get any hardware fault out of the picture.
When you boot your N2 from uSD card you can see/manipulate your eMMC installation. When opening Kodi File Manager, the âstorageâ partition on your eMMC installation will be shown in capital letters, as STORAGE and the one on uSD cars will show as storageâŚ
OK as long as I follow the correct guide Iâll be able to do this. I can find the correct OS download but on MACOS so the references to Rufus donât apply.
Is there an alternative for me?
Try with âBalena Etcher for MacOS 64â.
I use Ether all the time on Win machines, and for me it works perfectly
Appreciated.
Wish me luck 
Edit:
I progressed a bit furtherâŚ
Iâve used a microSD to install the image. I think the system did boot from this. I still have just the CE boot screen but there is an error displayed this time.
âStarting debugging shell for boot step: mount storageâŚtype exit to quitâ
âError in mount_storage: mount_common: Could not mount UUID= ################â
Well Iâm not there yetâŚ
I used a portable USB drive as I have no uSD cards here - is this an issue?
When I boot itâs stuck at the CE screen so itâs using the eMMC I think? I can try all 4 usb ports but some donât boot the sytem at all. I still can view the drive on the MAC with a pic of what I see.
Do I need to tell it to boot from USB?
Yes, as @kostaman says, and if your Petitboot version is older than 20200816, then youâll first have to update it to get it working â instructions here
Thanks for sticking with me guys.
SP1 switch on I get a black screen with menu though I donât know how to interact with it.
It does state petiboot v 20191213 so I need to get that updated then.
Also looks like the only SD card I have access to has become corrupt now too
Pull the eMMC out
Flash the SD Card again
Switch back to eMMC position on SPI switch
Boot up with just the SD Card
We have progress 
Following that instruction (with working SD card) has installed a fresh CE
So as it stands I now have a fresh install on SD and the eMMC is currently unattached.
I guess the hardware is functioning so where to go further to troubleshoot the original installation?
You can now disconnect power, attach your eMMC, and with uSD card inserted it should boot to uSD card installation.
In Settings choose âExpertâ mode, and in âInterfaceâ (I think) select to show hidden files/folder, and allow renaming/deleting files/folders.
Then I File Manager youâll see the mentioned eMMC STORAGE (in capitals) folder. In it navigate to Kodi/temp folder and check the log files for any errors.
Those settings are in âMediaâ
I canât quite get to the destination youâre asking. I think Iâm inside the eMMC section. I donât see folders for kodi or temp but do see a logfiles folder. In there are 10 logs from earlier today including a KODI.log
Is this the one I need to check?
OK, got it. All instructions I give you are done in Kodi.
First go to Settings (cog wheel on top row) then in Media. Here first choose âExpertâ mode (at the bottom left-> change from Basic to Standard to Advanced to Expert).
Then in same Settings/Media window choose âGeneralâ. Select ( set) all options to ON.
Then go back and open âFile managerâ. There click on âAdd sourceâ -> Browse -> choose âHome folderâ -> OK. It will offer âstorageâ as the name. This is your folder on uSD card.
There should be also a folder with same name in capital letters - STORAGE same one on your eMMCâŚ
I understand I should have been doing this within KODI not the Mac 
But I still canât reach what youâre suggesting. I do see the âstorageâ folder but there isnât a âSTORAGEâ folder anywhere. I have âmmcblk0p2-mmc-AJTD4R_0xa132d8câ which I can see is the old kodi on the eMMC. There I can navigate to .kodi > .temp > kodi.log / kodi.old.log but then do nothing with it (in File Manager)
OK, copy these logs from eMMC .kodi/temp to some thumb drive and look at them on Mac.
Or in File manager position on log file and long_press on it to bring up additional menu in which you can choose âView as textâ or something like that to open the contents of the log fileâŚ
Thank you.
Iâm looking for errors right?
2019-04-11 17:28:51.063 T:4064633424 ERROR: DBus error: org.freedesktop.DBus.Error.ServiceUnknown - The name org.freedesktop.UPower was not provided by any .service files
2019-04-11 17:28:51.226 T:4064633424 ERROR: GetString: error reading /storage/.kodi/userdata/disp_cap
2019-04-11 17:28:51.226 T:4064633424 ERROR: GetString: error reading /sys/class/amhdmitx/amhdmitx0/custom_mode
2019-04-11 17:28:51.226 T:4064633424 ERROR: GetString: error reading /storage/.kodi/userdata/disp_add
2019-04-11 17:28:51.226 T:4064633424 ERROR: GetString: error reading /run/disp_add
2019-04-11 17:28:51.809 T:3918496640 ERROR: SQL: [Textures13.db] SQLite error SQLITE_ERROR (no such table: version)
Query: SELECT idVersion FROM version
2019-04-11 17:28:51.810 T:3918496640 ERROR: Process error processing job
Or should I be looking somewhere else?
Donât know if your eMMC not booting problem will be shown in these log files.
If you suspect and donât need Plex, try to erase Plex folder from storage/.kodi/addons folder and also Plex from storage/.kodi/userdata/addon_data folder on eMMC.
Then power off, remove uSD card and try to boot from eMMCâŚ
