Firmware for Taz 5 for a Enlarged Y Axis bed?

I have recently increased my Taz 5 Y-axis bed and frame to now be 300x600. Everything works fine and all however i may have had the brains for making a proper enlarged bed that can function good and all but when it comes to the firmware for it i know very little. Wondering if anyone has done something similar and has the firmware/Hex file that can be installed via cura and to accompany a 600 mm bed.

From what i have looked into in the firmware i simply need the Y-max setting to be set at 600mm. since the current settings is around 275. since this setting can not be changed in the gcode. the firmware itself needs the change.

Ex. if your cura is set for 300x600. the Lulzbot will dumb the 600 down to 300 because that’s what the machine is calibrated as the Y-max

Soo please o please someone have that firmware