Moved @Alex 's work from here on PSRAM support to the 7r0 branch.
PICO_RUNTIME_INIT_FUNC_RUNTIME(runtime_init_setup_psram, PICO_RUNTIME_INIT_PSRAM);
It freezes during start up, due to something in the ‘runtime_init_setup_psram’ which is tied into runtime init like so. If you’re using the 7R0 branch for something else, comment out the runtime_init_setup_psram function to prevent freezing (or maybe this is just a my board bug 
).
I will look into this tomorrow if someone doesn’t spot my likely very obvious bug before then 
I created a psram command that attempts to allocate, fill, and test two chunks on memory.
The ‘disk’ storage is still NAND on the internal SPI bus (no Q). The firmware is burned to a NOR chip that shares the QSPI bus with the PSRAM chip. I think the intent was to suggest that the bug is one of three chips on the QSPI bus: RP2350, PSRAM or NOR flash.
Thank you, that is quite clear.