ESP32-S3 SPI Download Boot mode

[squire]

In addition to Joint Download Boot mode, the reference manual for the S3 mentions an SPI Download Boot mode, which I can trigger by holding GPIO0 LOW and GPIO46 HIGH on boot.
The documentation doesn't say much else about what SPI Download mode is, how to use it, or if it can be disabled like Joint Download mode can. I'm sure some applications might benefit from SPI Download mode over USB/UART Download but, at least for now, mine doesn't, so I'm curious if it's possible to disable it. That would give me ever-so-slightly more flexibility with my GPIO choices.