machines/systems/flexibot/docs/marlin/_gcode/M421.md

tag	title	brief	author	requires	group	related	codes	notes	parameters	examples
m0421	Set Mesh Value	Set a single mesh Z height	thinkyhead	AUTO_BED_LEVELING_(BILINEAR|UBL)|MESH_BED_LEVELING	motion	G29 M420	M421		tag optional description values I true X index into the mesh array type int tag optional description values J true Y index into the mesh array type int tag optional description values X true X position (which should be very close to a grid line) (`MESH_BED_LEVELING` only) tag type linear float tag optional description values Y true Y position (which should be very close to a grid line) (`MESH_BED_LEVELING` only) tag type linear float tag optional description values Z true The new Z value to set tag type linear float tag optional description values Q true A value to add to the existing Z value tag type linear float tag optional description values C true Set the mesh point closest to the current nozzle position (`AUTO_BED_LEVELING_UBL` only) type bool tag optional description values N true Set the mesh point to undefined (`AUTO_BED_LEVELING_UBL` only) type bool	pre code Set the Z height in the middle of a 5x5 grid M421 I2 J2 Z-0.05 pre code Set the same Z height using XY M421 X100 Y100 Z-0.05 pre code Adjust the mesh point by -0.01 M421 I2 J2 Q-0.01

This command is used to set a single Z value for a mesh point in the stored bed leveling data.

Allowed forms are M421 In Jn Zn, M421 Xn Yn Zn (MESH_BED_LEVELING only) or M421 C Zn (AUTO_BED_LEVELING_UBL only).