No big mistery of that:
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141
Ok, do you know how we can shift the place of bolded part? To make it look like this:
EBAAEDCE6AF48A03BBFD25E8CD0364141
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFOr even better, imagine this is target :
0x0000000000000000000000000000000000000000000000000000000001234567
Now how can we make it look like this:
FFFFFFFFFFFFFFFFFFFFFFFF
1234567EBAAEDCE6AF48A03BBFD25E8CD0364141
Lol, this is simple add or sub, to change all of those.
But for the last one, why would you take a smaller target and make it astronomically bigger?