Installing on Ubuntu 21.04

The flash drive.
Though, I did have one motherboard where the only way I found to install Linux was to boot and install from an actual DVD. (But that wouldn't even boot from the USB)

I seem to recall that the D525MW will only boot from some of the USB ports, not all of them. But if you are booting then you are past that roadblock.

My bet is a BIOS setting - often you need to do a hard boot (pull the power) after making BIOS setting changes. (Be sure the CMOS battery is fresh)

I've seen a couple of motherboards where I had to flash an update to a broken BIOS.

Sometimes. clearing the BIOS to defaults or using the CMOS battery jumper has got things going again.

Debian can install on UEFI BIOS if the BIOS is not full of bugs..

,.,.
I would bet on a BIOS setting or a buggy BIOS..

I have a very similar system, except it is the Gigabyte GA-D525STUD and I only have 2G of RAM. I'm also using the onboard graphics adapter. I had the same install problem you described when I tried to install Buster, but I got past the error:

At the "Detect and mount CD-ROM screen ... couldn't be mounted" screen, I pull the USB drive out and then reinsert it. Then I hit continue and the install goes fine after that.

Also, I tried the RTAI kernel for the Buster install but the system didn't seem to work as well as it did with Wheezy. I ended up buying a cheap ASRock J3355B (also ITX, but with a Celeron). It also has the USB install problem and the same fix works. I haven't been able to get the Buster RTAI to work on it yet, but it works great with Wheezy. It was discussed on this thread: forum.linuxcnc.org/38-general-linuxcnc-q...tency-mesage?start=0

pdxalz wrote: I have a very similar system, except it is the Gigabyte GA-D525STUD and I only have 2G of RAM. I'm also using the onboard graphics adapter. I had the same install problem you described when I tried to install Buster, but I got past the error:

At the "Detect and mount CD-ROM screen ... couldn't be mounted" screen, I pull the USB drive out and then reinsert it. Then I hit continue and the install goes fine after that.

Also, I tried the RTAI kernel for the Buster install but the system didn't seem to work as well as it did with Wheezy. I ended up buying a cheap ASRock J3355B (also ITX, but with a Celeron). It also has the USB install problem and the same fix works. I haven't been able to get the Buster RTAI to work on it yet, but it works great with Wheezy. It was discussed on this thread: forum.linuxcnc.org/38-general-linuxcnc-q...tency-mesage?start=0

I've used the exact same ASRock board and never had any issues with installation via USB. Did you try other USB sticks or did you only try the one ?

Buster installs fine now on both motherboards, D525 and J3355. (I'm not the original poster) The problem in my case appears to be how I created the bootable usb drive. Before, I created the bootable drive from my Windows PC using the Rufus program. It created a usable drive, but required unplugging and reinserting the usb drive.

When I used Buster to create the drive using "dd" it worked fine.

Also verision 3.11 of Rufus on Windows worked fine if I selected the "Write in DD mode" instead of the recommended "write in ISO image mode", after hitting the start button.

Well, I finally got this to work with The 2.8 iso and Buster. Removing the usb stick and resetting the BIOS to default values seemed to do the trick. I used Rufus to create the usb in iso mode.
Thanks to all for the help!!