Original Issue : Extruder 2 and 3 of Tricolour Mendal failed to extrude (no feed of filament for 2 and 3 extruder)
New Issue : Print 6% smaller than specified

Action taken : Reflashed Firmware with latest Marlin Multicolour files from GitHub to try resolve the Extruder issue.
Subsequently discovered print was 6% smaller than specified.
Reflashed Firmware with values for correct pulley type

Details:

R1: Print is 6% smaller. Change was made to Configuration.h on step size for X and Y pulley to reflect the correct pulley type

#define DEFAULT_AXIS_STEPS_PER_UNIT {92.635, 92.635, 4000, 660} // <- 17-tooth printed pulley

Compiled and upload the new values. No errors reported on compilation and upload.

R2: Extruder 2 and 3 still failed to extrude. All motors confirm working.

Setup and Versions of IDE and Hardware :

Arduino version : Arduino 1.0.6 IDE

Marlin Version : Mendel - Marlin Multicolur Version
VERSION_STRING "1.0.8 RRP"

Hardware : Sanguino Atmega 1284p 16 Mhz

Output : Reading from Sanguino Board (M501, M503)

Firmware version: V10, EEPROM version: V10
ok p : 12.00 i:2.20 d:80.00 w:125
echo : Stored settings retreived:
echo : Steps per unit:
echo : M92 X87.49 Y87.49 Z4000.00 E660.00

Value of X87.49 Y87.49 did not change to new value and retained old values.
Both boards jumpered for USB power and Reset ( JP1 and JP14) during firmware upload.

Seems like firmware not updated. Priority to resolve R1.

Any idea where it went wrong? Appreciate any advice given.

Flashing the firmware does not automatically reset the EEPROM to the new values.

You'll need to send the G-codes "M502" (reset values to values in firmware) and then "M500" (save current values to EEPROM).

Thanks Enif. M502 and M500 worked. Need to remember this step.
R1 resolved.