 Looks like it was an issue with VirtualBox. Got an updated version of VB n now the new iso build is getting installed.
 Forwarded from unknown: Ubuntu Unity 20.10 is now available for the Raspberry Pi!  🎉 It includes amd64-arm, which sets up an emulated Debian x86_64 (Stretch) environment. This would help you to run common 64-bit (amd64) programs on your Raspberry Pi.Details are available at: https://ubuntuunity.org/2020/12/01/ubuntu-unity-20-10-for-raspberry-pi/ :
 Forwarded from unknown: