Waveshare 4" ILI9486 display unhappiness

[elaw01887]

Hey, has anyone gotten this library working with this (or similar) display? https://www.waveshare.com/4inch-tft-touch-shield.htm

I see in the documentation this library works with some ILI9486-based Pi displays, but didn't know if it was supposed to work with others or not.

I've got the display connected to a generic ESP32 dev board as indicated in the attached file, and via the read_user_setup sketch have verified the library is picking up the correct I/O pins. I've double- and triple-checked my wiring, but the display won't do anything except turn on the backlight. I tried running the TFT_ReadWrite_Test sketch but it always seems to read back zeroes.

Edit: I forgot to mention, I know the display itself works! I plugged it into an Arduino Uno and ran the demo sketch that Waveshare supplies, and it worked fine.

User_Setup.h.txt