esp-idf/examples/system/startup_time/sdkconfig.defaults

# Set flash configuration as fast as possible (Quad I/O 80MHz)
#
# (Not all hardware may support this configuration.)
CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
CONFIG_ESPTOOLPY_FLASHFREQ_80M=y

# These two settings mean that no logs are printed
# during startup, but it's possible to use esp_log_level_set("*", ESP_LOG_INFO)
# at runtime to get Info-level logging back
CONFIG_LOG_DEFAULT_LEVEL_WARN=y
CONFIG_LOG_MAXIMUM_LEVEL_INFO=y
CONFIG_BOOTLOADER_LOG_LEVEL_WARN=y

# at risk of not detecting flash corruption, skip bootloader
# verification of the app unless a soft reset or crash happened
#
# note: the larger the application, the bigger the time saved by
# from this option
CONFIG_BOOTLOADER_SKIP_VALIDATE_ON_POWER_ON=y

# Setting option to zero is only recommended if not using sleep modes, or
# if you don't need accurate sleep times.
CONFIG_RTC_CLK_CAL_CYCLES=0