TR6 not applying, "insufficient space for LIC"

I was searching the archives and saw that the same ocurred for TR5 but i'll
explain:

9407-M15 machine with 900Gb ASP, 6% ASP usage (OS + the PTFs downloaded
from fixcentral).
Installed from a very very old resave of 7.1
Only detail is that it is missing the cache card for the onboard raid ctl
(no biggie, only VERY SLOW io) but it shouldnt affect a software matter.
Went to fixcentral, selected all groups for install. Pointed the java app
to the machine and let it ran overnight.
Today i found that some ptfs had io error downloading (usual stuff when
downloading 3500 ptfs at the same time).
Restarted the download and got all of them
go ptf option 8 from *SERVICE
Ends up saying
Insufficient storage for Licensed Internal Code fix.

Searching that error brings me to some cases where they ended up doing a
slip install with the TR's already applied. Since this is not feasible (we
are not an i shop, i just get some hardware and test things) i'm going the
round about way and doing APYPTF on every 5770999 ptf that lets me.
But i wanted to ask, is it normal not to be able to upgrade to TR6 from a
base 7.1 install? i find it hard to believe that the process would be
broken so...

Best Regards,