esp-iot-solution: Unable to use I2S LCD mode with 8-bit parallel

I have ported over an ILI9488 display with an init sequence that’s known to work on other libraries. However I’m noticing the code expects 16 bit commands/registers, and there are no provisions on the code to check for 8 bit data paths for registers. In fact it seems that the 8 bit defines are just plain wrong for the combination of displays with 8 bit commands and 8 bit bus (https://github.com/espressif/esp-iot-solution/blob/db36832d90b0077bc7fa5a455b789497f8a12911/components/i2s_devices/lcd_common/i2s_lcd_com.c#L36 is pretty telling in this regard).

When connected via a 16 bit bus the top byte/8 lines are ignored, but as far as I can tell on 8 bits bus the ILI commands are seemingly being cancelled by NOPs when the bytes are swapped (high byte is 0x0). I unfortunately can’t follow up on this suspicion right now as I don’t have a logic analyser handy. I do know that the connections are right and I do know that bit banging the GPIOs as a bus works. I suspect there could be something weird with the WS clock but first I’d like to make sure that my reading of i2s_lcd_com makes any sense…

For kicks, I also attempted to port over ILI9341 as 8-bit parallel I2S; everything is royally garbled there but I can see some thin strips with parts of what the original image is supposed to be. So I’m still hoping it’s just misconfigured somehow…