mpack wrote:512MB RAM is not very much for a 64bit guest OS. I would increase to 2048MB. Also give it 2 CPU cores (not more or less).
VirtualBox seems to behaving problems with the USB emulation on Linux hosts. Try disabling USB in the VM settings.
Also, is OpenWRT intended for PCs? I note that the VM errors out the instant it first tries to execute guest code.
I've been running several OpenWRT OS in virtualbox for years without major issues. OpenWRT does not require much memory unless a lot of extra software is running in the VM. I've never had to use more than 512MB for OpenWRT.
Even if it were the case that the OS needed more memory, grub certainly does not. We don't get anywhere close to a running OS. The VM fails just before grub loads, so this cannot have anything to do with the specific OS inside the VM. I think grub is designed to run with low resources.
When you say Virtualbox seems to be having problems with USB emulation, do you mean this latest version, 6.1.38? It was working well enough here previously.