[Xenon]

well, yes it's doable,
you have to edit user.php and usergroup.php

in user.php it's easy:

find:

PHP Code:

// ###################### Start do update #######################
if ($HTTP_POST_VARS['action']=="doupdate") { 


below add:

PHP Code:

if ($bbuserinfo[userid]!=1 and $userid!=$bbuserinfo[userid] and $usergroupid==6) {
  echo "You cannot make this user an Admin";
  exit;
} 


this should work, but he can also creat a new user, org give a whole usergroup adminpermissions...