im using v5.11.1 and the command line is " avrdude -p m128 -c usbasp -U flash:w:t.hex".
i never turn on the verify you referred to. in my experience if theres no problem the first time then it works the next million times so no need to verify. specially since verify takes several times longer than write.
there is no option to lower the boot address. even if that made much difference, which i dont think it would, client requires it to be in the top 256 bytes.
i developed this loader a couple years ago for smaller avr chips but now its needed for m128 and m1284. it works with any terminal program (no avrstudio or avrdude) because it accepts hex files directly instead of all that stk/109 baloney. also incorporates a bios which if im not mistaken is unique among bootloaders. and generally much faster than most isp programming.
i wonder why usbasp code to skip ff was deleted. is this the root of the problem? hard to believe since other programmers do it too. why cant avrdude skip unused locations? sounds like a bug to me. unfortunately im not in a position to modify usbasp or avrdude compiler code. only assembler atm. i see at least three others in recent posts in this forum similarly inconvenienced. and they are not involved in thousands of downloads like me. any other suggestions?