I am trying to use the article in Linux Format magazine for January 2022 : “Setting up Kodi” pp 34-35.
I have downloaded the 10.0.2 img.gz version of LibreELEC, but cannot understand how I should install it on my Pi400. {It’s not made clear in the article and the website quoted - Create Media - LibreELEC.wiki - is rather abstruse).
I understand that the inserted microSD card contains the Rasp OS so I can’t use that[?]. Apparently an img.gz is equivalent to an .iso in the PC world and would reformat the card[?].
A card came with the Pi400 but there is no slot for it on the keyboard. Is this to (somehow) just store files? I suspect I’m missing something! Can anyone steer me in the right direction please?
Perhaps I should use a USB stick instead?
Hopefully at least one of the Forum members is familiar with Kodi.
A Pi is able to boot in a few different ways, from a USB with an image installed or a micro SD card.
You can always overwrite the contents of the microSD card but if you want to swap between Rasp OS and LibreELEC I’d recommend getting another micro SD card.
To install the .img or iso file onto the micro SD card you can use Raspberry Pi imager or Balena Etcher
If you opt for the route of using Raspberry Pi Imager you don’t even need the 10.0.2 img.gz file. When you click on Choose OS, navigate through to the following > Media Player OS > LibreElec > the select the version for ‘RPI4’.
The larger card that came with the bundle is a microSD to full size SD adapter (the microSD is nestled inside the end).
A USB stick would also work, but can make the Pi 400 a bit more bulky.
An .iso and .img file is a raw copy of an image - this could be an operating system or a direct copy of a USB or hard drive.
Let the forum know if you have any more questions!
Liam > thanks for your interest. I am moving slowly I’m afraid; I intend
to get a second micro SD and then study the subject in depth.
I am currently up to Linux Format 285 (February) in my reading and
notice “Multiboot a Raspberry Pi” (pp46-49), which I haven’t read yet.
Will no doubt be an expert after your info and LXF’s article!
BTW : I knew that the large SD accepted the micro - think I found out
from the introductory book I read a few months’ ago - I had simply
forgotten!
Liam > you suggest purchasing a second micro SD card. OK, but what
capacity? The one I have is apparently 250MB - not absolutely sure. But
one of Core Electronic’s websites recommends 16GB minimum, so I am confused!
My progress is slower than a snail; but once I get started/motivated I
scream along . . . BTW I noticed that the Pi400 read a 16GB USB stick OK
but baulked (ignored) a 32GB stick. Maybe a FAT format rather than ext4?
Yeah a second microSD card would let you swap out the OS on your Pi super easily. I’d go for a 16 or 32GB card for the OS, if you need more storage (as you usually do when setting up a media center, you can move to a USB or network storage solution)
The 250 MB card that you have sounds like its partitioned and is picking up the readable portion on Windows.
Sounds familiar I’d definitely check the format of the USB sticks - blkid will let you see a lot of details about partitions connected to your Pi
I’d definitely check the format of the USB sticks - 
