Hi! I am working with MC9S08DZ60 controller. compiled with cosmic compiler and am using Trace32 debugger. I have divided my project into BOOT and Application. boot code resides in the flash from 0x8200 -> 0xFFFF. Application resides in the flash at 0x1900. and have built two .elf files separately for debugging. My issue is, when I use flash block protection feature in the DZ60, which is NVPROT register needs to be programmed with the value, the amount of flash needs to be protected(0xEA). After exit from reset, the high page register FPROT is loaded with the contents of the NVPROT location. and am trying to redirect the vector table by writing to NVOPT. I am unable to write to these NVPROT and NVOPT registers.except these location am able to program every byte of my .s19 file. This is a snippet of my S19 file: S11FE2403536372D303048573030323631343339372D3030000000000000000093 S106FFBDEAFFBF95 S123FFC0D4E1D4E189B688CA8B078BEBC137D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E1C5 S123FFE0D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E1D4E182FFE1 S123D4F98789879BC61825A5102705A610C71825957F2056A655C7180048C71800C61825B1 Am i missing somthing? If you guys can provide some solution, it's greatly helpful. Thanks in advance.