Rendered usb media not working using CLI version

[7FFY]

Distribution (run cat /etc/os-release):

NAME="Pop!_OS"
VERSION="19.10"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Pop!_OS 19.10"
VERSION_ID="19.10"
HOME_URL="https://system76.com/pop"
SUPPORT_URL="http://support.system76.com"
BUG_REPORT_URL="https://github.com/pop-os/pop/issues"
PRIVACY_POLICY_URL="https://system76.com/privacy"
VERSION_CODENAME=eoan
UBUNTU_CODENAME=eoan
LOGO=distributor-logo-pop-os

Related Application and/or Package Version (run apt policy $PACKAGE NAME):

Package files:
100 /var/lib/dpkg/status
release a=now
1001 http://ppa.launchpad.net/system76/pop/ubuntu eoan/main i386 Packages
release v=19.10,o=LP-PPA-system76-pop,a=eoan,n=eoan,l=Pop!_OS PPA,c=main,b=i386
origin ppa.launchpad.net
1001 http://ppa.launchpad.net/system76/pop/ubuntu eoan/main amd64 Packages
release v=19.10,o=LP-PPA-system76-pop,a=eoan,n=eoan,l=Pop!_OS PPA,c=main,b=amd64
origin ppa.launchpad.net
500 http://ppa.launchpad.net/mmstick76/ion-shell/ubuntu eoan/main i386 Packages
release v=19.10,o=LP-PPA-mmstick76-ion-shell,a=eoan,n=eoan,l=ion-shell,c=main,b=i386
origin ppa.launchpad.net
500 http://ppa.launchpad.net/mmstick76/ion-shell/ubuntu eoan/main amd64 Packages
release v=19.10,o=LP-PPA-mmstick76-ion-shell,a=eoan,n=eoan,l=ion-shell,c=main,b=amd64
origin ppa.launchpad.net
500 http://ppa.launchpad.net/fontforge/fontforge/ubuntu eoan/main i386 Packages
release v=19.10,o=LP-PPA-fontforge-fontforge,a=eoan,n=eoan,l=FontForge,c=main,b=i386
origin ppa.launchpad.net
500 http://ppa.launchpad.net/fontforge/fontforge/ubuntu eoan/main amd64 Packages
release v=19.10,o=LP-PPA-fontforge-fontforge,a=eoan,n=eoan,l=FontForge,c=main,b=amd64
origin ppa.launchpad.net
500 http://ppa.launchpad.net/agornostal/ulauncher/ubuntu eoan/main i386 Packages
release v=19.10,o=LP-PPA-agornostal-ulauncher,a=eoan,n=eoan,l=Ulauncher,c=main,b=i386
origin ppa.launchpad.net
500 http://ppa.launchpad.net/agornostal/ulauncher/ubuntu eoan/main amd64 Packages
release v=19.10,o=LP-PPA-agornostal-ulauncher,a=eoan,n=eoan,l=Ulauncher,c=main,b=amd64
origin ppa.launchpad.net
500 http://apt.pop-os.org/proprietary eoan/main all Packages
release v=19.10,o=system76,a=eoan,n=eoan,l=System76,c=main,b=all
origin apt.pop-os.org
500 http://apt.pop-os.org/proprietary eoan/main amd64 Packages
release v=19.10,o=system76,a=eoan,n=eoan,l=System76,c=main,b=amd64
origin apt.pop-os.org
100 http://us.archive.ubuntu.com/ubuntu eoan-backports/universe i386 Packages
release v=19.10,o=Ubuntu,a=eoan-backports,n=eoan,l=Ubuntu,c=universe,b=i386
origin us.archive.ubuntu.com
100 http://us.archive.ubuntu.com/ubuntu eoan-backports/universe amd64 Packages
release v=19.10,o=Ubuntu,a=eoan-backports,n=eoan,l=Ubuntu,c=universe,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-updates/universe i386 Packages
release v=19.10,o=Ubuntu,a=eoan-updates,n=eoan,l=Ubuntu,c=universe,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-updates/universe amd64 Packages
release v=19.10,o=Ubuntu,a=eoan-updates,n=eoan,l=Ubuntu,c=universe,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-updates/multiverse i386 Packages
release v=19.10,o=Ubuntu,a=eoan-updates,n=eoan,l=Ubuntu,c=multiverse,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-updates/multiverse amd64 Packages
release v=19.10,o=Ubuntu,a=eoan-updates,n=eoan,l=Ubuntu,c=multiverse,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-updates/restricted amd64 Packages
release v=19.10,o=Ubuntu,a=eoan-updates,n=eoan,l=Ubuntu,c=restricted,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-updates/main i386 Packages
release v=19.10,o=Ubuntu,a=eoan-updates,n=eoan,l=Ubuntu,c=main,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-updates/main amd64 Packages
release v=19.10,o=Ubuntu,a=eoan-updates,n=eoan,l=Ubuntu,c=main,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-security/universe i386 Packages
release v=19.10,o=Ubuntu,a=eoan-security,n=eoan,l=Ubuntu,c=universe,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-security/universe amd64 Packages
release v=19.10,o=Ubuntu,a=eoan-security,n=eoan,l=Ubuntu,c=universe,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-security/multiverse i386 Packages
release v=19.10,o=Ubuntu,a=eoan-security,n=eoan,l=Ubuntu,c=multiverse,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-security/multiverse amd64 Packages
release v=19.10,o=Ubuntu,a=eoan-security,n=eoan,l=Ubuntu,c=multiverse,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-security/restricted amd64 Packages
release v=19.10,o=Ubuntu,a=eoan-security,n=eoan,l=Ubuntu,c=restricted,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-security/main i386 Packages
release v=19.10,o=Ubuntu,a=eoan-security,n=eoan,l=Ubuntu,c=main,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan-security/main amd64 Packages
release v=19.10,o=Ubuntu,a=eoan-security,n=eoan,l=Ubuntu,c=main,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan/universe i386 Packages
release v=19.10,o=Ubuntu,a=eoan,n=eoan,l=Ubuntu,c=universe,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan/universe amd64 Packages
release v=19.10,o=Ubuntu,a=eoan,n=eoan,l=Ubuntu,c=universe,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan/multiverse i386 Packages
release v=19.10,o=Ubuntu,a=eoan,n=eoan,l=Ubuntu,c=multiverse,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan/multiverse amd64 Packages
release v=19.10,o=Ubuntu,a=eoan,n=eoan,l=Ubuntu,c=multiverse,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan/restricted i386 Packages
release v=19.10,o=Ubuntu,a=eoan,n=eoan,l=Ubuntu,c=restricted,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan/restricted amd64 Packages
release v=19.10,o=Ubuntu,a=eoan,n=eoan,l=Ubuntu,c=restricted,b=amd64
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan/main i386 Packages
release v=19.10,o=Ubuntu,a=eoan,n=eoan,l=Ubuntu,c=main,b=i386
origin us.archive.ubuntu.com
500 http://us.archive.ubuntu.com/ubuntu eoan/main amd64 Packages
release v=19.10,o=Ubuntu,a=eoan,n=eoan,l=Ubuntu,c=main,b=amd64
origin us.archive.ubuntu.com
Pinned packages:

Issue/Bug Description:

I tried to use popsicle cli (using i3) to put the latest 19.10 iso (intel) on
a usb stick. Everything went right during the process except that the rendered
usb stick was not usable at all. I was able to boot from it in the BIOS but
then I had an empty prompt with an infinite blancking underscore character.

The file structure on the usb key looks okay so I have no idea what's going on.
I did not used the check option (I never test my iso files, I know I'm bad :)).
When I switched back to the pop session however I used the GUI version, same
settings etc... and I was able to get a proper working usb stick using the
exact same iso.

I'm glad you guys provide us some nice tools (CLI and GUI) and I hope that
those infos could help to solve the issue...

Steps to reproduce (if you know):

Simply grab the latest intel iso and type in a shell $ popsicle /path/to/the/iso /path/to/the/usb/device
Wait until the shell prompt ask for new commands.
Reboot on the usb stick.
You're there!

[jwillikers]

Trying to re-create this issue, I was able to boot from the USB without incident.
I used the latest commit on master: 1a67cff to build Popsicle on Ubuntu 20.04.
I installed Pop!_OS 20.04 for Intel on the USB flash drive.
My system uses UEFI, by the way.

[ids1024]

Wiping a drive with dd from /dev/zero, flashing with popsicle in a terminal, it seems to boot fine.

There may be an issue here, but it's not clear how to reproduce it.