On a modern system (Windows 7+, Linux wth GRUB 2.0 bootloader) all of the drawing is done without the VBIOS; the VBIOS is just used to set up the mode.
The VBIOS is a 16-bit x86 application, but it does not run on these systems in vm86; reason being that mode is not supported in 64-bit long mode.
When the VBIOS does execute, it never does from Flash. SBIOS copies into system memory first.
Source: I’ve worked on VBIOS