8GByte in an embedded processor application ! I remember squeezing code into a 6805 with 8kbits (1kbyte) !
Yes that's why I want to give up on Linux. Have you had any luck finding a VL805 datasheet ? Or documentation from RPi on how they have used it ?
This would be very useful, perhaps as a sticky somewhere so we know what to expect when trying it out, or to keep an eye on to know when it's worth another try.
A friend has it working on Gentoo on x86 - it seems to be a Pi4 thing