Upgrade kernel for TC 3.x remix without upgrading user apps?

[harjoc]

I built a custom "recovery-cd" image based on TinyCore 3.x that consists of a compressed initrd and boots via bcdedit (like Ubuntu Wubi) instead of a physical CD. It has various recovery tools for partition editing, antivirus, etc.

Now I have to upgrade the kernel and modules to make it support UEFI, so it can boot in a SecureBoot-enabled machine (I'm using a signed grubx64.efi for booting). Upgrading usermode binaries to TC 5.x would be problematic on amd64 since my 64bit TC builds were entirely from source (as there was no 64bit Xorg in the TC 3.x days).

For now I replaced the 2.6.32 kernel and modules with 3.10 from TC 5.x and things appear to work. But TC 3.x has glibc 2.11, while TC 5.x has glibc 2.17.

My question is, how do I make sure there are no incompatibilities between the new kernel and older user apps/libs. I am looking out for removed syscalls and features in all kernel release notes between 2.6.32 and 3.10, but what would a more thorough approach be ? Am I just asking for trouble by doing this ?

[curaga]

What you did is completely supported. The kernel is very backwards compatible, syscalls are not removed, the ABI is only changed when absolutely necessary.

Everything should work fine, with the possible exception of udev - check the docs on the kernel you used for the minimum required udev version.

edit: There may be some tweaks needed in the boot scripts with module names, etc.