diff --git a/include/osmocom/bsc/gsm_04_08_rr.h b/include/osmocom/bsc/gsm_04_08_rr.h
index e2e861d..8e4f787 100644
--- a/include/osmocom/bsc/gsm_04_08_rr.h
+++ b/include/osmocom/bsc/gsm_04_08_rr.h
@@ -23,7 +23,8 @@
 			     struct msgb *msg, struct bsc_subscr *bsub);
 int gsm48_send_rr_classmark_enquiry(struct gsm_lchan *lchan);
 int gsm48_send_rr_ciph_mode(struct gsm_lchan *lchan, int want_imeisv);
-int gsm48_multirate_config(uint8_t *lv, const struct amr_multirate_conf *mr, const struct amr_mode *modes);
+int gsm48_multirate_config(uint8_t *lv, const struct gsm48_multi_rate_conf *mr_conf,
+			   const struct amr_mode *modes, unsigned int num_modes);
 struct msgb *gsm48_make_ho_cmd(struct gsm_lchan *new_lchan, uint8_t power_command, uint8_t ho_ref);
 int gsm48_send_ho_cmd(struct gsm_lchan *old_lchan, struct gsm_lchan *new_lchan,
 		      uint8_t power_command, uint8_t ho_ref);
diff --git a/src/osmo-bsc/bsc_vty.c b/src/osmo-bsc/bsc_vty.c
index f156cc8..08b5dad 100644
--- a/src/osmo-bsc/bsc_vty.c
+++ b/src/osmo-bsc/bsc_vty.c
@@ -4391,11 +4391,12 @@
 
 	mr.ms_mode[0].mode = amr_mode;
 	mr.bts_mode[0].mode = amr_mode;
+	mr.num_modes = 1;
 
 	/* encode this configuration into the lchan for both uplink and
 	 * downlink direction */
-	gsm48_multirate_config(lchan->mr_ms_lv, &mr, mr.ms_mode);
-	gsm48_multirate_config(lchan->mr_bts_lv, &mr, mr.bts_mode);
+	gsm48_multirate_config(lchan->mr_ms_lv, mr_conf, mr.ms_mode, mr.num_modes);
+	gsm48_multirate_config(lchan->mr_bts_lv, mr_conf, mr.bts_mode, mr.num_modes);
 
 	return 0;
 }
diff --git a/src/osmo-bsc/gsm_04_08_rr.c b/src/osmo-bsc/gsm_04_08_rr.c
index 35044a3..4659c1a 100644
--- a/src/osmo-bsc/gsm_04_08_rr.c
+++ b/src/osmo-bsc/gsm_04_08_rr.c
@@ -321,47 +321,113 @@
 	cd->arfcn_lo = bts->c0->arfcn & 0xff;
 }
 
-/*! \brief Encode a TS 04.08 multirate config LV according to 10.5.2.21aa
- *  \param[out] lv caller-allocated buffer of 7 bytes. First octet is IS length
- *  \param[in] mr multi-rate configuration to encode
- *  \param[in] modes array describing the AMR modes
- *  \returns 0 on success */
-int gsm48_multirate_config(uint8_t *lv, const struct amr_multirate_conf *mr, const struct amr_mode *modes)
+/*! \brief Encode a TS 04.08 multirate config LV according to 10.5.2.21aa.
+ *  \param[out] lv caller-allocated buffer of 7 bytes. First octet is is length.
+ *  \param[in] mr_conf multi-rate configuration to encode (selected modes).
+ *  \param[in] modes array describing the AMR modes.
+ *  \param[in] num_modes length of the modes array.
+ *  \returns 0 on success, -EINVAL on failure. */
+int gsm48_multirate_config(uint8_t *lv,
+			   const struct gsm48_multi_rate_conf *mr_conf,
+			   const struct amr_mode *modes, unsigned int num_modes)
 {
-	int num = 0, i;
+	int num = 0;
+	unsigned int i;
+	unsigned int k;
+	unsigned int m = 0;
+	bool mode_valid;
+	uint8_t *gsm48_ie = (uint8_t *) mr_conf;
+	const struct amr_mode *modes_selected[4];
 
+	/* Check if modes for consistency (order and duplicates) */
+	for (i = 0; i < num_modes; i++) {
+		if (i > 0 && modes[i - 1].mode > modes[i].mode) {
+			LOGP(DRR, LOGL_ERROR,
+			     "BUG: Multirate codec with inconsistant config (mode order).\n");
+			return -EINVAL;
+		}
+		if (i > 0 && modes[i - 1].mode == modes[i].mode) {
+			LOGP(DRR, LOGL_ERROR,
+			     "BUG: Multirate codec with inconsistant config (duplicate modes).\n");
+			return -EINVAL;
+		}
+	}
+
+	/* Check if the active set that is defined in mr_conf has at least one
+	 * mode but not more than 4 modes set */
 	for (i = 0; i < 8; i++) {
-		if (((mr->gsm48_ie[1] >> i) & 1))
+		if (((gsm48_ie[1] >> i) & 1))
 			num++;
 	}
 	if (num > 4) {
-		LOGP(DRR, LOGL_ERROR, "BUG: Using multirate codec with too "
-				"many modes in config.\n");
-		num = 4;
+		LOGP(DRR, LOGL_ERROR,
+		     "BUG: Multirate codec with too many modes in config.\n");
+		return -EINVAL;
 	}
 	if (num < 1) {
-		LOGP(DRR, LOGL_ERROR, "BUG: Using multirate codec with no "
-				"mode in config.\n");
-		num = 1;
+		LOGP(DRR, LOGL_ERROR,
+		     "BUG: Multirate codec with no mode in config.\n");
+		return -EINVAL;
 	}
 
+	/* Do not accept excess hysteresis or threshold values */
+	for (i = 0; i < num_modes; i++) {
+		if (modes[i].threshold >= 64) {
+			LOGP(DRR, LOGL_ERROR,
+			     "BUG: Multirate codec with excessive threshold values.\n");
+			return -EINVAL;
+		}
+		if (modes[i].hysteresis >= 16) {
+			LOGP(DRR, LOGL_ERROR,
+			     "BUG: Multirate codec with excessive hysteresis values.\n");
+			return -EINVAL;
+		}
+	}
+
+	/* Scan through the selected modes and find a matching threshold/
+	 * hysteresis value for that mode. */
+	for (i = 0; i < 8; i++) {
+		if (((gsm48_ie[1] >> i) & 1)) {
+			mode_valid = false;
+			for (k = 0; k < num_modes; k++) {
+				if (modes[k].mode == i) {
+					mode_valid = true;
+					modes_selected[m] = &modes[k];
+					m++;
+				}
+			}
+			if (!mode_valid) {
+				LOGP(DRR, LOGL_ERROR,
+				     "BUG: Multirate codec with inconsistant config (no mode defined).\n");
+				return -EINVAL;
+			}
+		}
+	}
+	OSMO_ASSERT(m <= 4);
+
+	/* When the caller is not interested in any result, skip the actual
+	 * composition of the IE (dry run) */
+	if (!lv)
+		return 0;
+
+	/* Compose output buffer */
 	lv[0] = (num == 1) ? 2 : (num + 2);
-	memcpy(lv + 1, mr->gsm48_ie, 2);
+	memcpy(lv + 1, gsm48_ie, 2);
 	if (num == 1)
 		return 0;
 
-	lv[3] = modes[0].threshold & 0x3f;
-	lv[4] = modes[0].hysteresis << 4;
+	lv[3] = modes_selected[0]->threshold & 0x3f;
+	lv[4] = modes_selected[0]->hysteresis << 4;
 	if (num == 2)
 		return 0;
-	lv[4] |= (modes[1].threshold & 0x3f) >> 2;
-	lv[5] = modes[1].threshold << 6;
-	lv[5] |= (modes[1].hysteresis & 0x0f) << 2;
+	lv[4] |= (modes_selected[1]->threshold & 0x3f) >> 2;
+	lv[5] = modes_selected[1]->threshold << 6;
+	lv[5] |= (modes_selected[1]->hysteresis & 0x0f) << 2;
 	if (num == 3)
 		return 0;
-	lv[5] |= (modes[2].threshold & 0x3f) >> 4;
-	lv[6] = modes[2].threshold << 4;
-	lv[6] |= modes[2].hysteresis & 0x0f;
+	lv[5] |= (modes_selected[2]->threshold & 0x3f) >> 4;
+	lv[6] = modes_selected[2]->threshold << 4;
+	lv[6] |= modes_selected[2]->hysteresis & 0x0f;
 
 	return 0;
 }
diff --git a/tests/gsm0408/Makefile.am b/tests/gsm0408/Makefile.am
index d790fc8..b207f8b 100644
--- a/tests/gsm0408/Makefile.am
+++ b/tests/gsm0408/Makefile.am
@@ -23,6 +23,7 @@
 	$(NULL)
 
 gsm0408_test_LDADD = \
+	$(top_builddir)/src/osmo-bsc/gsm_04_08_rr.o \
 	$(top_builddir)/src/osmo-bsc/arfcn_range_encode.o \
 	$(top_builddir)/src/osmo-bsc/gsm_data.o \
 	$(top_builddir)/src/osmo-bsc/gsm_timers.o \
diff --git a/tests/gsm0408/gsm0408_test.c b/tests/gsm0408/gsm0408_test.c
index bc2777d..faeca39 100644
--- a/tests/gsm0408/gsm0408_test.c
+++ b/tests/gsm0408/gsm0408_test.c
@@ -35,6 +35,8 @@
 #include <osmocom/gsm/sysinfo.h>
 #include <osmocom/gsm/gsm48.h>
 
+#include <osmocom/bsc/gsm_04_08_rr.h>
+
 #define COMPARE(result, op, value) \
     if (!((result) op (value))) {\
 	fprintf(stderr, "Compare failed. Was %x should be %x in %s:%d\n",result, value, __FILE__, __LINE__); \
@@ -799,6 +801,106 @@
 	OSMO_ASSERT(pass);
 }
 
+static void test_gsm48_multirate_config()
+{
+	uint8_t lv[7];
+	struct gsm48_multi_rate_conf *gsm48_ie;
+	struct amr_multirate_conf mr;
+	int rc;
+
+	memset(&mr, 0, sizeof(mr));
+
+	/* Use some made up threshold and hysteresis values */
+	mr.ms_mode[0].threshold = 11;
+	mr.ms_mode[1].threshold = 12;
+	mr.ms_mode[2].threshold = 13;
+	mr.ms_mode[0].hysteresis = 15;
+	mr.ms_mode[1].hysteresis = 12;
+	mr.ms_mode[2].hysteresis = 8;
+
+	gsm48_ie = (struct gsm48_multi_rate_conf *)&mr.gsm48_ie;
+	gsm48_ie->ver = 1;
+	gsm48_ie->m5_90 = 1;
+	gsm48_ie->m7_40 = 1;
+	gsm48_ie->m7_95 = 1;
+	gsm48_ie->m12_2 = 1;
+
+	/* Test #1: Normal configuration with 4 active set members */
+	mr.ms_mode[0].mode = 2;
+	mr.ms_mode[1].mode = 4;
+	mr.ms_mode[2].mode = 5;
+	mr.ms_mode[3].mode = 7;
+	rc = gsm48_multirate_config(lv, gsm48_ie, mr.ms_mode, 4);
+	OSMO_ASSERT(rc == 0);
+	printf("gsm48_multirate_config(): rc=%i, lv=%s\n", rc,
+	       osmo_hexdump_nospc(lv, lv[0]));
+
+	/* Test #2: 4 active set members, but wrong mode order: */
+	mr.ms_mode[3].mode = 2;
+	mr.ms_mode[2].mode = 4;
+	mr.ms_mode[1].mode = 5;
+	mr.ms_mode[0].mode = 7;
+	rc = gsm48_multirate_config(lv, gsm48_ie, mr.ms_mode, 4);
+	OSMO_ASSERT(rc == -EINVAL);
+
+	/* Test #3: Normal configuration with 3 active set members */
+	mr.ms_mode[0].mode = 2;
+	mr.ms_mode[1].mode = 4;
+	mr.ms_mode[2].mode = 5;
+	mr.ms_mode[3].mode = 0;
+	gsm48_ie->m12_2 = 0;
+	mr.ms_mode[2].threshold = 0;
+	mr.ms_mode[2].hysteresis = 0;
+
+	rc = gsm48_multirate_config(lv, gsm48_ie, mr.ms_mode, 3);
+	OSMO_ASSERT(rc == 0);
+	printf("gsm48_multirate_config(): rc=%i, lv=%s\n", rc,
+	       osmo_hexdump_nospc(lv, lv[0]));
+
+	/* Test #4: 3 active set members, but wrong mode order: */
+	mr.ms_mode[0].mode = 2;
+	mr.ms_mode[2].mode = 4;
+	mr.ms_mode[1].mode = 5;
+	rc = gsm48_multirate_config(lv, gsm48_ie, mr.ms_mode, 3);
+	OSMO_ASSERT(rc == -EINVAL);
+
+	/* Test #5: Normal configuration with 2 active set members */
+	mr.ms_mode[0].mode = 2;
+	mr.ms_mode[1].mode = 4;
+	mr.ms_mode[2].mode = 0;
+	gsm48_ie->m7_95 = 0;
+	mr.ms_mode[1].threshold = 0;
+	mr.ms_mode[1].hysteresis = 0;
+
+	rc = gsm48_multirate_config(lv, gsm48_ie, mr.ms_mode, 2);
+	OSMO_ASSERT(rc == 0);
+	printf("gsm48_multirate_config(): rc=%i, lv=%s\n", rc,
+	       osmo_hexdump_nospc(lv, lv[0]));
+
+	/* Test #6: 2 active set members, but wrong mode order: */
+	mr.ms_mode[1].mode = 2;
+	mr.ms_mode[0].mode = 4;
+	rc = gsm48_multirate_config(lv, gsm48_ie, mr.ms_mode, 2);
+	OSMO_ASSERT(rc == -EINVAL);
+
+	/* Test #7: Normal configuration with 1 active set member */
+	mr.ms_mode[0].mode = 2;
+	mr.ms_mode[1].mode = 0;
+	gsm48_ie->m7_40 = 0;
+	mr.ms_mode[0].threshold = 0;
+	mr.ms_mode[0].hysteresis = 0;
+
+	rc = gsm48_multirate_config(lv, gsm48_ie, mr.ms_mode, 1);
+	OSMO_ASSERT(rc == 0);
+	printf("gsm48_multirate_config(): rc=%i, lv=%s\n", rc,
+	       osmo_hexdump_nospc(lv, lv[0]));
+
+	/* Test #8: 0 active set members: */
+	mr.ms_mode[0].mode = 0;
+	rc = gsm48_multirate_config(lv, gsm48_ie, mr.ms_mode, 1);
+	OSMO_ASSERT(rc == -EINVAL);
+}
+
 static const struct log_info_cat log_categories[] = {
 };
 
@@ -839,6 +941,8 @@
 
 	test_gsm48_ra_id_by_bts();
 
+	test_gsm48_multirate_config();
+
 	printf("Done.\n");
 
 	return EXIT_SUCCESS;
@@ -854,3 +958,37 @@
 }
 
 void ts_fsm_alloc(struct gsm_bts_trx_ts *ts) {}
+
+void bsc_cm_update(struct gsm_subscriber_connection *conn,
+		   const uint8_t *cm2, uint8_t cm2_len,
+		   const uint8_t *cm3, uint8_t cm3_len) {}
+
+int rsl_siemens_mrpci(struct gsm_lchan *lchan, struct rsl_mrpci *mrpci)
+{ return 0; }
+
+int rsl_chan_mode_modify_req(struct gsm_lchan *ts) { return 0; }
+
+int rsl_tx_ipacc_crcx(struct gsm_lchan *lchan) { return 0; }
+
+void gscon_submit_rsl_dtap(struct gsm_subscriber_connection *conn,
+			   struct msgb *msg, int link_id, int allow_sacch) {}
+
+bool lchan_may_receive_data(struct gsm_lchan *lchan) { return  true; }
+
+int bsc_compl_l3(struct gsm_subscriber_connection *conn, struct msgb *msg,
+		 uint16_t chosen_channel) { return 0; }
+
+void bsc_dtap(struct gsm_subscriber_connection *conn, uint8_t link_id,
+	      struct msgb *msg) {}
+
+void bsc_cipher_mode_compl(struct gsm_subscriber_connection *conn,
+			   struct msgb *msg, uint8_t chosen_encr) {}
+
+const char *bsc_subscr_name(struct bsc_subscr *bsub) { return NULL; }
+
+void lchan_release(struct gsm_lchan *lchan, bool sacch_deact,
+		   bool err, enum gsm48_rr_cause cause_rr) {}
+
+int rsl_data_request(struct msgb *msg, uint8_t link_id) { return 0; }
+
+int rsl_encryption_cmd(struct msgb *msg) { return 0; }
diff --git a/tests/gsm0408/gsm0408_test.ok b/tests/gsm0408/gsm0408_test.ok
index 7270721..9424167 100644
--- a/tests/gsm0408/gsm0408_test.ok
+++ b/tests/gsm0408/gsm0408_test.ok
@@ -226,4 +226,8 @@
 test_gsm48_ra_id_by_bts[4]: digits='999999' lac=0xffff=htons(65535) rac=0xff=255 pass
 test_gsm48_ra_id_by_bts[5]: digits='09f909' lac=0xcdab=htons(43981) rac=0xab=171 pass
 test_gsm48_ra_id_by_bts[6]: digits='090990' lac=0xcdab=htons(43981) rac=0xab=171 pass
+gsm48_multirate_config(): rc=0, lv=0620b40bf330
+gsm48_multirate_config(): rc=0, lv=0520340bf3
+gsm48_multirate_config(): rc=0, lv=0420140b
+gsm48_multirate_config(): rc=0, lv=0220
 Done.