writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	etag := getDecryptedETag(formValues, objInfo, false)

	// We must not use the http.Header().Set method here because some (broken)
	// clients expect the ETag header key to be literally "ETag" - not "Etag" (case-sensitive).
	// Therefore, we have to set the ETag directly as map entry.
	w.Header()[xhttp.ETag] = []string{`"` + etag + `"`}