Yes, the pass-through mode is pretty easy to use (and functionality was proven on MPW-one because at least the housekeeping SPI worked). The program

test/caravel_hkflash.py

in the

caravel

repository is the easiest way to program the flash. All you need to do to use pass-through mode is to access the housekeeping SPI and send the single-byte command

03

, after which all SPI data goes straight to the flash chip until CSB is raised. The script uses the Python

pyftdi

library, so it's pretty universally compatible (although I have had difficulty with Windows WSL due to accessing low-level device drivers).