srec_cat and Arduino bootloader/usbserial/usbdfu

Hello,

I have been trying to merge the usbserial and usbdfu hex "out of the box" files from Github i.e. no changes to the code. Make files set to the Uno board. After running make and then using srec_cat with the intel options I get an error.

Command used: srec_cat Arduino-usbdfu.hex -intel Arduino-usbserial.hex -intel -o USAduino.hex -intel

Error message: 257: contradictory 0x00001000 value (previous =0x4B, this one = 0x77)

Is there some setting that needs to be coordinated between the usbserial and the usbdfu source/make files so that the hex files will merge properly? Or maybe srec parameters to ignore the "fatal error"

p.s. I know the merged hex file version exist already but I am trying to learn a few things. I am not intimate with the memory space nor srec for that matter etc.... so I do not know how to make sense of the error....as of yet...

zg