Dario,

Reviewing the '420 on-chip debugger "command list" (on page 184 of the '420 User's Guide), i don't see any instruction that references "program memory" beyond the internal 16k FLASH.

However there is a Load External RAM command which can program to the full 64k of data.

Since you want your program in non-volatile memory anyway, perhaps you might place your SRAM device in the DATA MEM page for downloading, switch it into program space for execution.

regards,
p