Yes, in fact this is the simplest method of updating an Alesis HD24.

Simply connect the machines via 2 MIDI cables (in to out and out to in, as usual).

On the older machine, select MIDI page 3 (Software Load Code?), it will ask "Completely erase old code?" and answer Yes.

On the newer machine, select MIDI pabe 4 (Software Send Code?), it will ask "Send out OS code?) and answer Yes.

In about 5 minutes, your older-OS machine will be updated.