IDA Pro can deal with the Renesas H8 processors, but not the free version.
Are there any free or low cost (<£100) disassemblers for the Renesas H8 family or processors?
Reverse Engineering Stack Exchange is a question and answer site for researchers and developers who explore the principles of a system through analysis of its structure, function, and operation. It only takes a minute to sign up.Sign up to join this community
There is an H8 port of GNU binutils (the target is called 'h8300' I believe) which includes
objdump. It seems it's even available in Debian in the package
binutils-h8300-hms (might be outdated).
Alternative GNU-based toolchains for many Renesas processors (including H8) are provided by KPIT (free but requires registration). I think they've been contributing to mainline too but not sure how's their progress there.
Just for reference, here's how to use
objdump to disassemble a raw binary:
objdump -m h8300 -b binary -D myfile.bin
Renesas offers their own commercial compiler/assembler/simulator (and I think a disassembler too) suite called High-performance Embedded Workshop (HEW) but I couldn't find out how much it costs. There is a downloadable evaluation version, however.
For a quick look at some hex you can also try the Online Disassembler, it has a couple of H8 variants.