HAOS installed on internal SSD, but won't boot without SD card in the slot?

I’m new to HA and have zero knowledge about Linux, Ubuntu, Python, and coding in general, or pretty much anything that involves typing commands in rather than clicking on them in a menu. So I apologies in advance as I might not understand all of the terminology being used, or how to do some of the things that I’m being asked to do.

As the title says, I have HAOS installed on the local SSD, but HA won’t boot at all without the original SD card that I used for the installation in the slot

What I wanted to do

I wanted to install Home Assistant OS on an old x86 based PC. I wanted it on the local SSD, and for it to be self contained on that SSD.

What I thought I was doing

I can’t find the original tutorial that I used, but it was pretty close to the official one.

I downloaded the official x86 version of the HAOS installation image, put the image on to an SD card using Etcher, and then booted to it. I then followed the prompts to install HAOS on to the local SSD.

I rebooted and everything seemed perfect, so I built my automation system and went my merry way.

At least this is what I thought I was doing. Somewhere along the way I did something wrong, and I’m not sure what it was, or when it was.

What actually happened

I’ve some how managed to install HAOS in such a way that it’s dependent on the SD card being in the slot.

When I remove the SD card from the slot and try to reboot my system it simply comes to the default BIOS (or whatever it’s called these days) screen telling me that there is no boot able disc available.

If I put the SD card back in and reboot, everything is peachy.

At first I thought that this meant that I’d installed HAOS on to the SD card somehow, but whenever I look at anything in HAOS it tells me that it’s on the SSD and it doesn’t even mention the SD card existing.

For example, if I look at the amount of disc space it reports the exact size of the SSD as being the total amount of space available, and the remaining space available is exactly what you’d expect for a new install of HAOS on an SSD of that size.

Not the SD.

At first I thought that this was just boot priorities or something, so I went into the Bios/UFEI and checked everything, and made sure that it was set to boot from the internal disc, not the SD, I even disabled the SD card reader, and each time it refused to boot.

Any combination except boot from SD if available, and then SSD if no SD card is present just causes it to stop booting on the generic No bootable media found message.

Again, I’m new to this, so some or all off the above may be wrong (but it’s definitely reporting the correct disc space for the SSD, not the SD).

Does anyone have any ideas, has this every happened to anyone before, and is this an installation problem or a BIOS\UFEI problem.

I’m using an old intel I3 CPU on a Great Wall Motherboard, and I’m doing most of this remotely at the moment so I can’t see the screen, and am having to ask someone to reboot it for me and read the messages. So response times are going to be slow.

I’d rather not completely reinstall it as I’m afraid of making things worse. At the moment it runs perfectly well with the SD card in, and I don’t want to start over.