PROVIDE(ets_delay_us = 0x4000d888);
PROVIDE(ets_update_cpu_frequency_rom = 0x4000d8a4);
PROVIDE(rom_i2c_writeReg = 0x4000a9a8);
PROVIDE(rom_i2c_writeReg_Mask = 0x4000aa00);
PROVIDE(rtc_get_reset_reason = 0x4000ff58);