Hi and thanks for the replie's, i have now sorted this problem by fitting a different spares number which had the updated microcode in the boot block.
What made this tricky was that another engineer had fitted 4 systemboards all with the same sps number 619557-001 which HP say was fitted to the serial number of z420 but they all would not boot due to the v2 XEON CPU not detecting correctly, the last of these 4 systemboards would boot ok with a v1 XEON fitted and the boot block was 2011, so what i did was ordered another systemboard with sps 708615-001 which part surfer listed along with 619557-001 for the product number of the z420.
Just incase you was wondering the v2 CPU is the original spec as sold by HP and not upgraded.
So, if the original systemboard from HP was 619557-001 so why then the following 4 systemboards with the same sps number not detect the v2 cpu.??
There must be a way to update the microcode on these systemboards!