Can we downgrade VxWorks 653 BSP to VxWorks 5.5?

Hello,

I have a BSP for SBC750GX that is available for VxWorks 653 version 2.2. I also have VxWorks 5.5, but for this version I only have the BSP template (PPC).

My question is:

Can we downgrade or adapt the VxWorks 653 BSP to work with VxWorks 5.5?

Thanks in advance for your guidance.