  We prove that the pullback of the SU(n)-soliton of Chern class $c_2=1$ over
$\mathbb S^4$ via the radial projection $\pi:\mathbb
B^5\setminus\{0\}\to\mathbb S^4$ minimizes the Yang-Mills energy under the
fixed boundary trace constraint. In particular this shows that stationary
Yang-Mills connections in high dimension can have singular sets of codimension
5.
