Gday Mozzie
If you load ASU 5.6, it will automatically want to grab the new ASU 5.8
This ASU mainly covers support for new handboxes and scope types.
The 5BE2 firmware is only associated with the new 497EP handboxes
If you are running an old 497 ( with 43Eg etc ),
then you cannot ( must not ) load 5BE2 into it, as it WILL kill it and require a safeload to recover.
If you do have a 497EP, then you really should use 5BE2 as it fixes some rather nasty bugs in 59Ef.
Andrew