You can boot live then download parrot & burn to USB while running live version (if you have enough ram). This is exactly what I had to do when unetbootin gave me a bad install.
Ensure settings in bios are correct for booting/installation on your machine. Default settings may not boot… For myself that meant disabling secureboot & enabling UEFI in preparation for installation/boot. Newer machines can be especially fickle.
If you want to use dd command (replacing /dev/sdc with your media device and parrot iso with exactly location of .iso image:
sudo dd status=progress if=parrot-security-4.2_amd64.iso of=/dev/sdc
So I had similar issue to you. I had an unusable system and I was able to download the parrot.iso file and burn it while using the live distro. This all depends how much RAM you have but to be safe don’t use any other apps to conserve that ram for the burning process.
Let me know how it goes