before amend of C1:
C3---C2---C1   <- master
           \
            \---A1---A2   <- A

after amend of C1:
C3---C2---C1'   <- master
      \
       \---C1---A1---A2   <- A

what git tries to do if i checkout A, rebase master:
C3---C2---C1'   <- master
           \
            \---C1---A1---A2     <- A

what I want instead:
C3---C2---C1'   <- master
           \
            \---A1---A2     <- A