diff --git a/include/osmo-bts/bts.h b/include/osmo-bts/bts.h
index 6b5fe6fe5..0fff2a5f5 100644
--- a/include/osmo-bts/bts.h
+++ b/include/osmo-bts/bts.h
@@ -53,24 +53,28 @@ enum gsm_bts_type_variant {
 };
 const char *btsvariant2str(enum gsm_bts_type_variant v);
 
-/* TODO: add a brief description of this flag */
-#define BTS_INTERNAL_FLAG_MS_PWR_CTRL_DSP		(1 << 0)
-/* When this flag is set then the measurement data is included in
- * (PRIM_PH_DATA) and struct ph_tch_param (PRIM_TCH). Otherwise the
- * measurement data is passed using a separate MPH INFO MEAS IND.
- * (See also ticket: OS#2977) */
-#define BTS_INTERNAL_FLAG_MEAS_PAYLOAD_COMB		(1 << 1)
-/* Whether the BTS model requires RadioCarrier MO to be in Enabled state
- * (OPSTARTed) before OPSTARTing the RadioChannel MOs. See OS#5157 */
-#define BTS_INTERNAL_FLAG_NM_RCHANNEL_DEPENDS_RCARRIER	(1 << 2)
-/* Whether the BTS model reports interference measurements to L1SAP. */
-#define BTS_INTERNAL_FLAG_INTERF_MEAS			(1 << 3)
+enum bts_impl_flag {
+	/* TODO: add a brief description of this flag */
+	BTS_INTERNAL_FLAG_MS_PWR_CTRL_DSP,
+	/* When this flag is set then the measurement data is included in
+	 * (PRIM_PH_DATA) and struct ph_tch_param (PRIM_TCH). Otherwise the
+	 * measurement data is passed using a separate MPH INFO MEAS IND.
+	 * (See also ticket: OS#2977) */
+	BTS_INTERNAL_FLAG_MEAS_PAYLOAD_COMB,
+	/* Whether the BTS model requires RadioCarrier MO to be in Enabled state
+	 * (OPSTARTed) before OPSTARTing the RadioChannel MOs. See OS#5157 */
+	BTS_INTERNAL_FLAG_NM_RCHANNEL_DEPENDS_RCARRIER,
+	/* Whether the BTS model reports interference measurements to L1SAP. */
+	BTS_INTERNAL_FLAG_INTERF_MEAS,
+
+	_BTS_INTERNAL_FLAG_NUM, /* must be at the end */
+};
 
 /* BTS implementation flags (internal use, not exposed via OML) */
 #define bts_internal_flag_get(bts, flag) \
-	((bts->flags & (typeof(bts->flags)) flag) != 0)
+	((bts->flags & (typeof(bts->flags))(1 << flag)) != 0)
 #define bts_internal_flag_set(bts, flag) \
-	bts->flags |= (typeof(bts->flags)) flag
+	bts->flags |= (typeof(bts->flags))(1 << flag)
 
 struct gprs_rlc_cfg {
 	uint16_t parameter[_NUM_RLC_PAR];
diff --git a/src/common/vty.c b/src/common/vty.c
index 331d27dc6..b17800c98 100644
--- a/src/common/vty.c
+++ b/src/common/vty.c
@@ -1228,10 +1228,10 @@ static void bts_dump_vty_features(struct vty *vty, const struct gsm_bts *bts)
 
 	vty_out(vty, "  BTS model specific (internal) flags:%s", VTY_NEWLINE);
 
-	for (i = 0, no_features = true; i < sizeof(bts->flags) * 8; i++) {
-		if (bts_internal_flag_get(bts, (1 << i))) {
+	for (i = 0, no_features = true; i < _BTS_INTERNAL_FLAG_NUM; i++) {
+		if (bts_internal_flag_get(bts, i)) {
 			vty_out(vty, "    %03u ", i);
-			vty_out(vty, "%-40s%s", get_value_string(bts_impl_flag_desc, (1 << i)), VTY_NEWLINE);
+			vty_out(vty, "%-40s%s", get_value_string(bts_impl_flag_desc, i), VTY_NEWLINE);
 			no_features = false;
 		}
 	}