Can I mix an ebi hand with an elf?

I have a product whose loader and application are compiled using a compiler (gnuarm GCC 4.1.1) that generates an "arm-elf".

The bootloader and the application are separated in different areas of FLASH memory in the script builder.

The application has a function that allows it to call the bootloader (as a simple c-function with two parameters).

I need to be able to update existing products around the world, and I can safely do this, always using the same compiler.

Now I would like to compile this product application using the new version of GCC, which displays arm-eabi.

Everything will be fine for new products, where both applications and the bootloader are compiled using the same toolchain, but what happens with existing products? If I run a new application compiled with GCC 4.6.x and arm-none-eabi, will my application still be able to call the bootloader function from the old arm-elf bootloader?

Also, not directly related to the question above, can I combine object files compiled with elves into a binary compiled with arm-eabi?

EDIT:

I think it's good to clarify what I'm building for ARM7 bare metal if it has any meaning ...