Compare Fail if you use -D option to not erase before write about mega-isp HOT 7 OPEN

These are two hex file the lamp.hex is the program that I want to flash and his 
result after a flash with -D

They are similar but not equal!

You have to erase the flash before you can reprogram it. Why would you not 
erase the flash?

That's strange, Arduino upload programs with a "-D" option, always, before 
programming. It is so wrong with flash?

Without "-D" avrdude erase flash AND EEPROM, with my radio Turnigy 9X I have to 
setup again all my parameter.

Before new contents can be written to the Flash Program Memory, the memory has 
to be
erased. Without erasing, it is only possible to program bits in Flash memory to 
zero, not selectively setting a bit to one. 

Arduino is a special case. What you're seeing is expected behavior.

It is possible to erase only a page (256byte) before writing it without erasing 
all flash AND eeprom?

Not with SPI programming. There is only one 'erase' command, to erase the whole 
chip. Arduino uses self-programming which does allow 'erase page' for flash. 
You'd have to install a bootloader on the mega8 chip to get this feature. 
Alternatively you could store a copy of the eeprom with your settings on it and 
then restore it each time you reflash the chip.