Assembling/Disassembling to/from RAW File for m32r Processor

[Stephen Done]

I need to disassemble some code for an m32r series processor, and then also
possibly recompile the code later on.

The object file I have is completely raw - i.e. it is 128kb dump of the ROM
that the processor executes when it boots. So there is no ELF (or any other
type of) header on the file.

Having built binutils with m32r-elf support, as expected, I get the error
  'File format not recognized'
when using objdump.

Should I have built binutils with a slightly different option to allow it to
interpret raw files ?
Is it possible to make objdump (or another suitable tool) convert this file
to assembler ?
Is it also then possible to recompile this assembler to a 'raw' format with
no headers, suitable for blowing back to ROM ?

Thanks for any help

Steve