General Notes

Adding this content here is to improve the user’s development efficiency and avoid stepping into known problems.

1. Bootloader

V3.1 updated the bootloader to initialize SPI flash I/O mode and clock. So if you are using the V3.0 bootloader, and now upgrade to the new SDK, please disable the following configuration in the menuconfig:

"Bootloader config  --->
    [ ] Bootloader init SPI flash"

2. Sniffer or Smartconfig

We moved some functions from IRAM to flash, including malloc and free fucntions, to save more memory. In this case, please do not read/write/erase flash during sniffer/promiscuous mode.

You need to disable the sniffer/promiscuous mode at first, then read/write/erase flash.

3. ESP8285 or ESP8266 + 1MB flash

ESP8285 or ESP8266 + 1MB flash can use “Copy OTA Mode” for OTA, more details are in the examples/system/ota.

4. JTAG I/O

In some cases, if enable JTAG I/O (default options), it will cost some more current so that the hardware will cost more power. So if users don’t use Jtag or these GPIOs directly and want to save more power, please enable this option in the menuconfig:

"Bootloader config  --->
    [ ] Bootloader disable JTAG I/O"