Marlin: EEPROM checksum mismatch

[MoonshineSG]

Today, dec 14, after updating to latest codes (I was behind a couple of weeks) i now get error on M501

Send: M501
Recv: Error:EEPROM checksum mismatch
Recv: echo:Hardcoded Default Settings Loaded

I tried to save, reset, save again etc, nothing works.

[Kaibob2]

I can confirm. Do you have set #define EXTRUDERS 2 or any other value than 1?
If so, try setting #define EXTRUDERS 1 this fixed the whole EEPROM behaviour in my test right now.
It would be nice if you could confirm this.
I suppose this happened somewhere here #5448
Maybe @thinkyhead can take a look at it.

This in configuration.h

// This defines the number of extruders
// :[1, 2, 3, 4]
#define EXTRUDERS 2

// Enable if your E steppers or extruder gear ratios are not identical
//#define DISTINCT_E_FACTORS

results in

on connection with Pronterface.

This in configuration.h

// This defines the number of extruders
// :[1, 2, 3, 4]
#define EXTRUDERS 1

// Enable if your E steppers or extruder gear ratios are not identical
//#define DISTINCT_E_FACTORS

results in

on connection with Pronterface.

[MoonshineSG]

@Kaibob2 yes, the error occurs with 2 extruders and once I change to #define EXTRUDERS 1 the EEPROM is loaded without error.

[Kaibob2]

This is what I expected
@thinkyhead Would you mind taking a look at your EEPROM refinement. Like it is now it's a PITA to print with any other extruder than E0 :(

[Kaibob2]

It would also be nice to have the ability to hardcode the PID values for each extruder.
And the home offset would also be a candidate for hardcoding it.

[Kaibob2]

Until this is fixed i reverted to configuration_store.cpp V27

[Kaibob2]

@esenapaj Tested right now. Works perfect. All values are stored and recovered after reset.
Good job!! Please make a PR out of it that it get's merged asap.

[esenapaj]

@MoonshineSG @Kaibob2
@thinkyhead has prepared a different solution for resolving it.
https://github.com/MarlinFirmware/Marlin/pull/5524 (Report EEPROM data size, not final index)

[MoonshineSG]

updated and the fix works.
Thanks!