Maybe it’s also something about the ISO files:
isoinfo -d -J -p -R -i nixos-minimal-20.03.2843.14006b724f3-x86_64-linux.iso
Setting input-charset to 'UTF-8' from locale.
CD-ROM is in ISO 9660 format
El Torito VD version 1 found, boot catalog is in sector 55
Joliet with UCS level 3 found, Joliet volume descriptor:
System id:
Volume id: nixos-minimal-20
Volume set id:
Publisher id: nixos
Data preparer id: XORRISO-1.5.2 2019.10.26.180001, LIBISOBURN-1.5.2, LIBISOFS-1.5.
Application id: nixos
Copyright File id:
Abstract File id:
Bibliographic File id:
Volume set size is: 1
Volume set sequence number is: 1
Logical block size is: 2048
Volume size is: 282112
SUSP signatures version 1 found
Rock Ridge signatures version 1 found
Rock Ridge id 'RRIP_1991A'
Eltorito validation header:
Hid 1
Arch 0 (x86)
ID ''
Cksum AA 55 OK
Key 55 AA
Eltorito defaultboot header:
Bootid 88 (bootable)
Boot media 0 (No Emulation Boot)
Load segment 0
Sys type 0
Nsect 4
Bootoff 5193 20883
isoinfo -d -p -R -i archlinux-2020.08.01-x86_64.iso
Setting input-charset to 'UTF-8' from locale.
CD-ROM is in ISO 9660 format
System id:
Volume id: ARCH_202008
Volume set id:
Publisher id: ARCH LINUX <HTTP://WWW.ARCHLINUX.ORG>
Data preparer id: PREPARED BY MKARCHISO
Application id: ARCH LINUX LIVE/RESCUE CD
Copyright File id:
Abstract File id:
Bibliographic File id:
Volume set size is: 1
Volume set sequence number is: 1
Logical block size is: 2048
Volume size is: 343552
El Torito VD version 1 found, boot catalog is in sector 44
NO Joliet present
SUSP signatures version 1 found
Rock Ridge signatures version 1 found
Rock Ridge id 'RRIP_1991A'
Eltorito validation header:
Hid 1
Arch 0 (x86)
ID ''
Cksum AA 55 OK
Key 55 AA
Eltorito defaultboot header:
Bootid 88 (bootable)
Boot media 0 (No Emulation Boot)
Load segment 0
Sys type 0
Nsect 4
Bootoff 802D 32813