so here is the sdk 1.5.3.3 upgrade patch for Arduino esp8166 2.3.0 package.
ESP8266_NONOS_SDK_V1.5.3.3_patch release notes for ESP8266 Arduino IDE
This patch is based on the ESP8266_NONOS_SDK_V1.5.3 and contains all changes updated within ESP8266_NONOS_SDK_V1.5.3.1
and ESP8266_NONOS_SDK_V1.5.3.2. When this patch is used:
1) .a files in this patch shall replace corresponding files under
the (D:\arduino\portable\packages)\esp8266\hardware\esp8266\2.3.0\tools\sdk\lib Folder (first part of path will vary
according to your installation).
2) core_esp8266_rf_cal.c must be copied to (D:\arduino\portable\packages)\esp8266\hardware\esp8266\2.3.0\cores\esp8266
folder (first part of path will vary according to your installation).
original description from espressif SDK release note:
https://espressif.com/en/support/downlo ... d%5B%5D=14
Optimisation:
1. Resolved the issue that API system_adc_read may return wrong value. (Resolved in 1.5.3.1)
2. Resolved the issue that the current in light sleep mode is too high. (Resolved in 1.5.3.1)
3. Optimised igmp to resolve the issue that ESP8266 maybe reset if connected to a special router. (Resolved in 1.5.3.1)
4. Resolved an issue that RF_Init_data sector may be broken in stress test. Provided a function "user_rf_cal_sector_set"
which has to be added in application by software developer. More details about user_rf_cal_sector_set refer to
documentation "2C-ESP8266__SDK__API Guide".(Resolved in ESP8266_NONOS_SDK_V1.5.3.2)
5. Fix a potential risk that will cause rf not work after external reset.(Resolved in ESP8266_NONOS_SDK_V1.5.3.3)
6. Modify 112 byte of esp_init_data_default.bin, 0x03->0x00, turn off auto freq correction.
ESP8266_NONOS_SDK Note:
esp_init_data.bin has to be downloaded into flash at least once.
Download blank.bin to initialize the sector stored RF_CAL parameter (set by user_rf_cal_sector_set),
and download esp_init_data.bin into flash, when the system needs to be initialized, or RF needs to be calibrated again.
(I think they refer to esp_init_data_default.bin)
have fun,
schufti