[RGB Light Platform] Remember brightness and color after restart about esphome-core HOT 5 CLOSED

Exactly. ESPHome doesn't use the EEPROM functionality because of a few reasons:

• Limited number of write cycles, if some component writes a lot of updates you will wear out the flash over time.
• Slow. Writing to flash on the ESP8266 is slow, when erasing a page for writing you can get delays of up to a couple hundred milliseconds if I remember correctly.
• Buggy. The ESP8266 EEPROM implementation is known to be unstable when using the hw timer at the same time (for example for PWM)
  I'm closing this because it's a won't fix - and there are other issues like this one in the issue tracker already.

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ESP8266s do not have any persistent NVRAM. They can remember states across reboots, but not power loss - so this might be only partially achieveable.

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ESP8266 have EEPROM builtin, do you think this might be used? I used it in past in some simple sketches.

#include <EEPROM.h>

https://arduino-esp8266.readthedocs.io/en/latest/libraries.html
Examples: https://github.com/esp8266/Arduino/tree/master/libraries/EEPROM

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On ESP8266 it is faked with flash memory, which has a limited number of write cycles.

EEPROM library uses one sector of flash located just after the SPIFFS

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I see this issue too - but wonder if either via the HA API or MQTT if esphome devices can read HA in some way and restore the "on" and "colour" value back to the before power lost state ?

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