I'm running into some new problems with the initial bootup and connect of the module. I have been trying software fixes but they're not working, so it might not be a software fixable issue. I am not sure if it's related to the 2.5v voltage issues or not. But I'm now thinking of experimenting with putting one of those 3.3v linear regulators on my new replacement Betz board (in place of the 2.5v one at "U4" on the schematic).

My prior Betz board, I had done that, but only after I'd already fried the I2S inputs on the chip. And then when I tried to put 3.3v into the thing it got real hot.

Did you say that you'd already done the 3.3v regulator swap on your Betz board, and that yours did NOT run hot when you did that? If so, I'll try it on mine.

I'm also thinking of ditching the Betz board altogether and going for getting a bare WT32i and a bare FTDI chip for programming it. Looking at the Betz schematic, there's not much there than what I'm already implementing on my interface between it and the Arduino:

- The aforementioned linear regulator with two 0.1uf smoothing caps.
- The FTDI chip with 0.1uf caps on its reset pin and DTR pin, and two 47pf caps on the incoming data pins from the USB plug.
- An LED and a resistor to watch its LED0 pin.
- The C16 470uF cap on the BATT line that I'm not sure is needed (is it?).
- A few connections such as VREG_ENA to BATT, some grounds, and the connections to the FTDI chip.

Everything else I don't need: Most of it is analog input stuff that I won't be using. The few other connections which are needed, I'm already implementing via my interface board to the Arduino. Does that seem about right?