This won't lead to homebrew, sorry guys.

The EBOOT has common bits, most probably either because of the structure of the file itself, or if it is an update, the part of the code that does all the flashing etc.
With the structure, I'm talking about how the file is put together, and how it is loaded etc. A good way to demonstrate this, is renaming the 1.50 update file to a .RES file, and opening it in a program such as "Resource Hacker", which shows how alike the file structures are.
And with the code, it is most of the stuff EXCEPT the actual contents of the updated Flash0 sector. This can be code such as the GUI, debugging, the calling of various functions such as "sceLflashFatfmtStartFatfmt", which formats the flash, or even the code which copys the data itself.

Please also remember that ALL EBOOTS are edit-protected, due to various checksums, size and content checkers, and a whole array of other data protection.

Don't give up though, even though editing an EBOOT is likely never to change the path of PSP hacking, there is always the hope that unsigned code will some day be unleashed on 2.70+!

Of course, the easiest way to avoid this situation is NOT to upgrade past v2.60!

__________________