"Card Mount Failed" on first boot only.

[samuelskottenborg]

I'm trying to append to a log file, but suddenly SD works very inconsistently. I'm pretty sure it just suddenly started, but I tried so many things I can't remember it so I'm a little uncertain on that part.

When I power on the ESP32 with the SD card module I get the error message "Card Mount Failed" from the sketch, but when I reset the ESP32 via the button or ESP.restart() it will work almost every time on second try.

So naturally I thought to myself it would be a power problem, I then added a cap, no luck. After that I added 1000ms delay in the setup(), still no luck. I also tried powering the SD module externally.

I have two identical setup with same problem on both. It can be reproduced with the standard SD_Test sketch included in the ESP32 package.

It might be related to this? #259
I tried the fix from there with custom SPI, still no luck (stopped working at all).

I'm running Windows 10 with the Arduino IDE 1.8.7 (also tried reinstalling).

This is my connections:
CS: D5
MISO: D19
MOSI: D23
SCK: D18

[samuelskottenborg]

I found the issue. It turns out some of my SD cards (they are properly formatted) only works after the ESP has been reset without losing power. Don't ask my why that is the case.