PROVIDE(ets_delay_us = 0x40008534);
PROVIDE(ets_update_cpu_frequency_rom = 0x40008550);
PROVIDE(rom_i2c_writeReg = 0x400041a4);
PROVIDE(rom_i2c_writeReg_Mask = 0x400041fc);
PROVIDE(rtc_get_reset_reason = 0x400081d4);