Unable to boot Linux Mint on Dell Inspiron all-in-one 5420

@RoHe​ 

Hey, thanks for the reply. I used Rufus to create a bootable usb flash drive just days after LM 21.3 was released in January. No different than what I did in 2018 and many times after that. As I said, I use LM since 2018, and have so far worked in LM 17, 20, and 21, with their various distros. I know how to setup bios to boot LM from a flash drive, trust me on this, as I've done it multiple times on a Toshiba laptop, a Dell Vostro 3568 laptop, and a Dell PC optimized for Windows XP (Dell Optiplex 745).

I created this bootable usb flash drive through Rufus, on a Windows 10 Dell Optiplex 3020, which my mom uses as her home computer. I used the usb flash drive to install the OS at least twice in the meantime. I even started suspecting the usb flash drive went bad in the meantime, so I tried booting LM on the said OptiPlex 3020, just minutes ago. It works just fine. I also went through BIOS setup on that PC to double check and compare with what I need. Everything there is setup just the way I need it too: secure boot off, no ssd partitioning, uefi mode, and AHCI. 

As you can see, I have numerous Dell products, so I am most familiar with them, and I used to trust them. Until now.

1. Boot mode is set to UEFI, as there is nothing else. 
2. Boot sequence is set to run LM from a usb flash drive. I set it up myself. However, I have a strange situation, where I see two boot drives with LM. For just in case, I set up their order to the beginning, then the rest of the suggested options. This new Boot options UI seems to offer booting from a usb drive as a temporary option only, and only AFTER you plug in your usb flash drive. If it's not plugged it, this option is nowhere to be found. I find this utmost strange.
3. I have not tried disabling Microsoft UEFI CA because I have no idea what it is, nor did I see it mentioned anywhere online.

What I can notice is that BIOS setup is so much more complex than what I am used to, the graphics and the UI are modern and very much like the regular OS. In older PCs and laptops, even the Dell Vostro laptop and the Dell OptiPlex 3020, the UI and the graphics are so minimal, pixelized letters, and the like. Likewise, boot options are much more straightforward, and easier to get the hang of. When I start Boot options on this AIO 5420, it's kind of scary to see so many options for everything. You do not want to mess something up here.

I am typing all this on this new PC, and can't tell you how much I am annoyed by Edge, by autocomplete text, by commercials and notifications popping up literally EVERYWHERE, I am bombarded by useless information wherever I look. I just can't handle it. 

All in all, I am highly disappointed by Dell if they made it impossible for us to run anything but Win on their PCs.

@bradthetechnut​ 

Yeah, that's the 2023 model, the only difference being I bought it a few months later.

I know that they say that they support Windows OS, but as @bradthetechnut said, unsupported does not always mean not working. I never actually expected they would make it impossible to boot anything other than the preinstalled Win! Go figure, why??? In the past, for the past 20 years, this has NEVER been the case, and there was always the possibility of using an OS of your choice. At least it wasn't forbidden to install a different one, and you were never forced to use what others impose on you.

Such customer policy by Dell is a no-go for me.

I still have slim hopes of finding a workaround. 

Just an epilogue to the story. Turns out, Ubuntu can be booted, but Linux Mint 21.3 Cinnamon (LTS) CANNOT. I took the PC to a professional, who had to disable secure boot, update BIOS, re-enable secure boot (I think), and what not, and only then boot the newest Linux Mint 21.3 Cinnamon Edge (which is meant to be used when other distros or flavour are unsupported by the hardware...). Understandably, after so much trouble with it, he completely wiped off the pre-installed Windows.

I am shocked and appalled by such work ethics of Dell. This is definitely my last Dell PC. Never again!!!

I don't think you can blame Dell for this one. I bet other OEM PCs have similar issues.  Microsoft has required lots of changes to BIOS lately. So there are obviously major changes if Linux Mint 21.3 Cinnamon Edge runs but Mint 21.3 Cinnamon (LTS) won't run. I doubt they created Cinnamon Edge just for Dell PCs. I did suggest you post the problem on the Cinnamon forum, where somebody could have been able to assist you.

Strongly suggest you open BIOS setup and copy all current BIOS settings, now that Cinnamon Edge is running, and save that info somewhere accessible, to be safe...

Microsoft UEFI CA is a security feature that checks to make sure drivers are "signed" (approved) by Microsoft and stored in a database on the motherboard. Wouldn't be surprised if it blocked the Linux installation, since it's enabled by default on the Inspiron 5420 AIO.

In fact there was a recent update to the 2023 Microsoft UEFI CA database that's "required for Linux, Option ROMs, etc, to continue booting". So maybe your PC didn't have this latest update from Microsoft for Cinnamon (LTS) and/or LTS isn't included in the latest database but Edge is included...

Yes you can, Dell say no To save having to develop drivers for a minority, however you can install Linux mint edge version which is the most stable version with the kernel constantly updated, I have one Inspiron 3501 working debian but before it had mint, if you are not sure manjaro is also an incredibly good option or zorin 17 much more beautiful and functional than windows 11, greetings!

<Your other Post was removed due to Code of Conduct violations. DELL-Admin>