Using oscilloscope, I found correct pin functions in SPI(SSP) boot mode:
P3.3 - SSP0_CK,
P3.6 - SSP0_SSEL,
P3.7 - SSP0_MISO,
P3.8 - SSP0_MOSI
Please check and correct Table 19 in Chapter 5.3 of user manual UM10503.
And what about "program mode" in DFUSec tool?
I don't find it in lpc_dfusec_v0.98aNS. There is only HDR/RAW mode...