anchor.diff:    (let ((major (nibbles:ub16ref/le header 32))
           (minor (nibbles:ub16ref/le header 34)))
       (when (not (and (eql major 0)
  -                    (eql minor 24)))
  +                    (eql minor 26)))
         (error "Image has unsupported protocol version ~D.~D.~%" major minor))
       (let* ((uuid (subseq header 16 32))
              (entry-fref (nibbles:ub64ref/le header 40))
              (initial-thread (nibbles:ub64ref/le header 48))
              (nil-value (nibbles:ub64ref/le header 56))
  -           (architecture (nibbles:ub32ref/le header 64))
  +           (architecture (aref header 64))
  +           (initial-stack-pointer (nibbles:ub64ref/le header 72))
              (bml4 (nibbles:ub64ref/le header 96))
              (freelist (nibbles:ub64ref/le header 104)))
         (list :uuid uuid
  
positive.code:     (setf (nibbles:ub64ref/le data 40) (getf header :entry-fref))
      (setf (nibbles:ub64ref/le data 48) (getf header :initial-thread))
      (setf (nibbles:ub64ref/le data 56) (getf header :nil-value))
      (setf (nibbles:ub32ref/le data 64) (encode-architecture (getf header :architecture)))
      (setf (nibbles:ub64ref/le data 96) (getf header :bml4))
      (setf (nibbles:ub64ref/le data 104) (getf header :freelist))
      data))
  
negative.code:                             (1 :x86-64)
                              (2 :arm64)
                              (t `(:unknown ,architecture)))
              :initial-stack-pointer initial-stack-pointer
              :bml4 bml4
              :freelist freelist))))
  
  