Xen installer cannot bring CPUs online

[graysmither <graysmither@xxxxxxxxxxxxxx>]

Hi

I'm trying to install Qubes R4.0.4 on a Legion 5 with AMD Ryzen 7 4800h and Nvidia Geforce 1660Ti. After some regular troubleshooting (running the installer under legacy boot mode and with nouveau disabled) it gets to Xen outputting the following error message with 5 second intervals:

“(XEN) Not responding”

“(XEN) Failed to bring up CPU i (error -5)”

which repeats for i from 1 to # of CPU threads . The code that's generating it seems to be from /xen/arch/x86/setup.c, which calls cpu_up(), which itself, calls __cpu_up(). Does anyone have any idea on what the source of the problem might be and how to solve the issue? 

Thanks