The Ethiopian Orthodox Tewahedo Church restricts access to a single guardian monk and has never permitted independent examination of the chapel contents, so the claim rests on church tradition alone.
What would resolve this An examination conducted by the church itself, or release of any documentary or photographic record it holds, since outside access is not permitted.
OpenBiblical archaeology, Ethiopian studiesChurch of Our Lady Mary of Zion, Aksum (Ethiopian Orthodox Tewahedo Church)