ESP32 trying to boot from HSPI

[sebo_b]

Hi,

I have the following problem on one of the boards: it is trying to boot from HSPI Flash, which doesn't exist. I've checked strapping pins and eFUSEs, and all looks correct, especially that esptool, by default, flashes SPI flash.

I'm getting the following message from bootloader:

Code: Select all

rst:0x10 (RTCWDT_RTC_RESET),boot:0xb (HSPI_FLASH_BOOT)
flash read err, 1000
ets_main.c 371
ets Jun  8 2016 00:22:57

I found this on the documentation webpage:

PI Mode:
(...)
During normal booting, this configuration is selected if all SPI pin efuses are unset and GPIO1 (U0TXD) is not pulled low (default).
(...)
HSPI Mode:
(...)
During normal booting, this configuration is selected if all SPI pin efuses are unset and GPIO1 (U0TXD) is pulled low on reset.

I will check GPIO1 if it is not pulled down, but it shouldn't be. Anyway, there is no such info in the ESP32 spec; it just comes from the esptool/Advanced Options webpage. So I'm not even sure if GPIO1 is another kind of undocumented strapping pin?

So, what may be the reason that the bootloader defaults to HSPI instead of FAST_SPI boot?