Memory usage:
Program static ram used: 45740
Dynamic ram used: 41876
Recycled dynamic ram: 2496
Current stack ram used: 2856
Maximum stack ram used: 5288
Never used ram: 2904
Last reset 04:24:53 ago, cause: power up
Last software reset code & available RAM: 0x0003, 3404
Spinning module during software reset: GCodes

Its on a wired duet 0.6

Date is as it was in the heightmap file, just a cut and paste.

Erm!!!

Bed probe has been working great with grid of S40 and S20,
Though I would try a "high res" probe to see how flat the bed was rather than just how level
so tried a S15 grid which at 100 points maxes the grid on my duet 0.6
an got..
RepRapFirmware height map file v1 generated at 0116-10-30 12:17
xmin,xmax,ymin,ymax,radius,spacing,xnum,ynum
40.00,180.00,30.00,170.00,-1.00,15.00,10,10
0.017,0.103,0.102,0.094,0.089,0.092,0.129,0.105,0.100,0.112
0.025,0.116,0.067,0.094,0.125,0.118,0.020,0.086,0.049,0.064
0.084,0.119,0.149,0.122,0.123,0.112,0.087,0.052,0.059,0.129
0.061,0.081,0.111,0.091,0.147,0.123,0.101,0.082,0.052,0.092
0.156,0.143,0.127,-0.016,0.100,0.094,0.056,0.081,0.059,0.038
0.201,0.144,0.116,0.030,0.062,-0.057,0.008,-0.012,0.029,0.035
0.200,0.139,-0.027,0.060,0.057,-0.079,-0.069,-0.030,-0.026,0.001
0.185,0.103,-0.002,0.223,0.030,0.028,0.010,-0.002,-0.021,-0.005
0.116,0.126,0.135,0.086,0.082,-0.036,-0.295,-0.069,-0.100,-0.049
-2.146,0.014,0.117,54548584975029841690624.000,-54548584975029841690624.000,54574818442859274829824.000,2572610785247232.000,2155874671919104.000,12844309018214137856.000,-0.126

Something rather stage happened at the end
This is reproducable, a second run gave
RepRapFirmware height map file v1 generated at 0116-10-30 12:26
xmin,xmax,ymin,ymax,radius,spacing,xnum,ynum
40.00,180.00,30.00,170.00,-1.00,15.00,10,10
0.005,0.088,0.093,0.082,0.086,0.084,0.114,0.098,0.087,0.089
0.014,0.095,0.046,0.086,0.116,0.095,0.001,0.082,0.031,0.042
0.064,0.105,0.133,0.114,0.112,0.093,0.080,0.031,0.051,0.122
0.057,0.077,0.094,0.086,0.132,0.116,0.088,0.064,0.035,0.085
0.140,0.137,0.120,-0.040,0.087,0.086,0.047,0.076,0.055,0.026
0.198,0.136,0.113,0.024,0.059,-0.053,-0.004,-0.017,0.024,0.022
0.192,0.133,-0.047,0.039,0.044,-0.099,-0.082,-0.038,-0.037,-0.002
0.164,0.088,-0.017,0.210,0.014,0.016,-0.004,-0.020,-0.039,-0.014
0.096,0.117,0.126,0.081,0.060,-0.051,-0.321,-0.093,-0.114,-0.047
0.047,0.023,0.097,54548584975029841690624.000,-54548584975029841690624.000,54574818442859274829824.000,2572610785247232.000,2155874671919104.000,12844309018214137856.000,-0.146

Reducing the grid slightly to 9x9 works as expected
RepRapFirmware height map file v1 generated at 0116-10-30 12:34
xmin,xmax,ymin,ymax,radius,spacing,xnum,ynum
40.00,180.00,30.00,170.00,-1.00,16.00,9,9
0.013,0.065,0.107,0.113,0.109,0.133,0.147,0.118,0.113
0.077,0.058,0.083,0.092,-0.157,0.064,-0.177,0.131,0.131
0.122,0.163,0.134,0.129,0.096,0.237,0.030,0.086,0.107
0.032,0.005,0.052,0.015,0.090,0.085,0.015,0.141,0.071
0.144,0.070,0.013,-0.023,0.116,-0.003,0.020,0.003,-0.013
0.123,0.077,0.119,0.086,0.061,0.041,0.044,0.055,-0.003
0.085,0.115,0.112,0.054,-0.171,-0.390,0.057,0.007,-0.015
0.106,0.155,0.076,0.085,0.057,0.022,-0.007,-0.053,-0.015
0.135,0.130,0.071,0.080,0.065,0.032,-0.039,-0.054,-0.043

Looks like the memory block for the 10x10 grid might be a tad too small and the end is getting overwritten ?

Chris