Installer crashed during VirtualBox installation from amd64 iso

[Jonas D.]

near-default settings, powerful machine, 8GB allocated memory

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity 20.04.15
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
Uname: Linux 5.4.0-26-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.445
CurrentDesktop: ubuntu:GNOME
Date: Thu Apr 30 10:47:46 2020
InstallCmdLine: file=/cdrom/preseed/ubuntu.seed initrd=/casper/initrd quiet splash --- maybe-ubiquity
LiveMediaBuild: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 LC_NUMERIC=C.UTF-8
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Sebastien Bacher (seb128)]

Thank you for your bug report. From the log
SQUASHFS error: zlib decompression failed, data probably corrupt
which indicates a corruption, please check your ram/disk and maybe record the iso again on another media and try again

[Jonas D. (jonasd-be)]

Iso was mounted directly via Virtualbox, redoing the entire installation seemed to have worked, but having issues doing an apt update or installing build-essentials. Verified integrity of the ISO.

Besides above issues every time I try to type something in "start" my screen resolution also resetted to ~800x600