diff --git a/nimble/controller/src/ble_ll_conn.c b/nimble/controller/src/ble_ll_conn.c
index 03930660f..4c93391cd 100644
--- a/nimble/controller/src/ble_ll_conn.c
+++ b/nimble/controller/src/ble_ll_conn.c
@@ -3788,11 +3788,9 @@ ble_ll_conn_rx_isr_end(uint8_t *rxbuf, struct ble_mbuf_hdr *rxhdr)
                         /*  XXX: TODO need to check with phy update procedure.
                          *  There are limitations if we have started update */
                         rem_bytes = OS_MBUF_PKTLEN(txpdu) - txhdr->txinfo.offset;
-                        if (rem_bytes > connsm->eff_max_tx_octets) {
-                            txhdr->txinfo.pyld_len = connsm->eff_max_tx_octets;
-                        } else {
-                            txhdr->txinfo.pyld_len = rem_bytes;
-                        }
+                        /* Adjust payload for max TX time and octets */
+                        rem_bytes = ble_ll_conn_adjust_pyld_len(connsm, rem_bytes);
+                        txhdr->txinfo.pyld_len = rem_bytes;
                     }
                 }
             }
@@ -4133,6 +4131,13 @@ err_slave_start:
     return 0;
 }
 
+#define MAX_TIME_UNCODED(_maxbytes) \
+        ble_ll_pdu_tx_time_get(_maxbytes + BLE_LL_DATA_MIC_LEN, \
+                               BLE_PHY_MODE_1M);
+#define MAX_TIME_CODED(_maxbytes) \
+        ble_ll_pdu_tx_time_get(_maxbytes + BLE_LL_DATA_MIC_LEN, \
+                               BLE_PHY_MODE_CODED_125KBPS);
+
 /**
  * Called to reset the connection module. When this function is called the
  * scheduler has been stopped and the phy has been disabled. The LL should
@@ -4174,42 +4179,32 @@ ble_ll_conn_module_reset(void)
     }
 
     /* Get the maximum supported PHY PDU size from the PHY */
+    max_phy_pyld = ble_phy_max_data_pdu_pyld();
 
     /* Configure the global LL parameters */
     conn_params = &g_ble_ll_conn_params;
-    max_phy_pyld = ble_phy_max_data_pdu_pyld();
 
-    /* NOTE: this all assumes that the default phy is 1Mbps */
     maxbytes = min(MYNEWT_VAL(BLE_LL_SUPP_MAX_RX_BYTES), max_phy_pyld);
     conn_params->supp_max_rx_octets = maxbytes;
 #if MYNEWT_VAL(BLE_LL_CFG_FEAT_LE_CODED_PHY)
-    conn_params->supp_max_rx_time =
-        ble_ll_pdu_tx_time_get(maxbytes + BLE_LL_DATA_MIC_LEN,
-                               BLE_PHY_MODE_CODED_125KBPS);
+    conn_params->supp_max_rx_time = MAX_TIME_CODED(maxbytes);
 #else
-    conn_params->supp_max_rx_time =
-        ble_ll_pdu_tx_time_get(maxbytes + BLE_LL_DATA_MIC_LEN, BLE_PHY_MODE_1M);
+    conn_params->supp_max_rx_time = MAX_TIME_UNCODED(maxbytes);
 #endif
 
     maxbytes = min(MYNEWT_VAL(BLE_LL_SUPP_MAX_TX_BYTES), max_phy_pyld);
     conn_params->supp_max_tx_octets = maxbytes;
 #if MYNEWT_VAL(BLE_LL_CFG_FEAT_LE_CODED_PHY)
-    conn_params->supp_max_tx_time =
-        ble_ll_pdu_tx_time_get(maxbytes + BLE_LL_DATA_MIC_LEN,
-                               BLE_PHY_MODE_CODED_125KBPS);
+    conn_params->supp_max_tx_time = MAX_TIME_CODED(maxbytes);
 #else
-    conn_params->supp_max_tx_time =
-        ble_ll_pdu_tx_time_get(maxbytes + BLE_LL_DATA_MIC_LEN, BLE_PHY_MODE_1M);
+    conn_params->supp_max_tx_time = MAX_TIME_UNCODED(maxbytes);
 #endif
 
     maxbytes = min(MYNEWT_VAL(BLE_LL_CONN_INIT_MAX_TX_BYTES), max_phy_pyld);
     conn_params->conn_init_max_tx_octets = maxbytes;
-    conn_params->conn_init_max_tx_time =
-        ble_ll_pdu_tx_time_get(maxbytes + BLE_LL_DATA_MIC_LEN, BLE_PHY_MODE_1M);
-    conn_params->conn_init_max_tx_time_uncoded =
-        ble_ll_pdu_tx_time_get(maxbytes + BLE_LL_DATA_MIC_LEN, BLE_PHY_MODE_1M);
-    conn_params->conn_init_max_tx_time_coded =
-        ble_ll_pdu_tx_time_get(maxbytes + BLE_LL_DATA_MIC_LEN, BLE_PHY_MODE_CODED_125KBPS);
+    conn_params->conn_init_max_tx_time = MAX_TIME_UNCODED(maxbytes);
+    conn_params->conn_init_max_tx_time_uncoded = MAX_TIME_UNCODED(maxbytes);
+    conn_params->conn_init_max_tx_time_coded = MAX_TIME_CODED(maxbytes);
 
     conn_params->sugg_tx_octets = BLE_LL_CONN_SUPP_BYTES_MIN;
     conn_params->sugg_tx_time = BLE_LL_CONN_SUPP_TIME_MIN;
diff --git a/nimble/controller/src/ble_ll_conn_priv.h b/nimble/controller/src/ble_ll_conn_priv.h
index a03dc61ae..02e99ed8a 100644
--- a/nimble/controller/src/ble_ll_conn_priv.h
+++ b/nimble/controller/src/ble_ll_conn_priv.h
@@ -27,14 +27,11 @@ extern "C" {
 #endif
 
 /*
- * Definitions for max rx/tx time/bytes for connections
- *  NOTE: you get 327 usecs from 27 bytes of payload by:
- *      -> adding 4 bytes for MIC
- *      -> adding 2 bytes for PDU header
- *      -> adding 8 bytes for preamble (1), access address (4) and crc (3).
+ * Definitions for min/max RX/TX time/bytes values allowed for connections.
+ * Source: Core 5.0 specification, Vol 6, Part B, section 4.5.10
  */
 #define BLE_LL_CONN_SUPP_TIME_MIN           (328)   /* usecs */
-#define BLE_LL_CONN_SUPP_TIME_MAX           (2120)  /* usecs */
+#define BLE_LL_CONN_SUPP_TIME_MAX           (17040) /* usecs */
 #define BLE_LL_CONN_SUPP_TIME_MIN_UNCODED   (328)   /* usecs */
 #define BLE_LL_CONN_SUPP_TIME_MAX_UNCODED   (2120)  /* usecs */
 #define BLE_LL_CONN_SUPP_TIME_MIN_CODED     (2704)  /* usecs */
diff --git a/nimble/controller/src/ble_ll_ctrl.c b/nimble/controller/src/ble_ll_ctrl.c
index 49d14c7d7..072b5d7e9 100644
--- a/nimble/controller/src/ble_ll_ctrl.c
+++ b/nimble/controller/src/ble_ll_ctrl.c
@@ -161,35 +161,6 @@ ble_ll_ctrl_rej_ext_ind_make(uint8_t rej_opcode, uint8_t err, uint8_t *ctrdata)
     ctrdata[1] = err;
 }
 
-static int
-ble_ll_ctrl_chk_supp_bytes(uint16_t bytes)
-{
-    int rc;
-
-    if ((bytes < BLE_LL_CONN_SUPP_BYTES_MIN) ||
-        (bytes > BLE_LL_CONN_SUPP_BYTES_MAX)) {
-        rc = 0;
-    } else {
-        rc = 1;
-    }
-
-    return rc;
-}
-
-static int
-ble_ll_ctrl_chk_supp_time(uint16_t t)
-{
-    int rc;
-
-    if ((t < BLE_LL_CONN_SUPP_TIME_MIN) || (t > BLE_LL_CONN_SUPP_TIME_MAX)) {
-        rc = 0;
-    } else {
-        rc = 1;
-    }
-
-    return rc;
-}
-
 #if (BLE_LL_BT5_PHY_SUPPORTED == 1)
 /**
  * Called to cancel a phy update procedure.
@@ -226,10 +197,10 @@ ble_ll_ctrl_len_proc(struct ble_ll_conn_sm *connsm, uint8_t *dptr)
     ctrl_req.max_tx_bytes = get_le16(dptr + 4);
     ctrl_req.max_tx_time = get_le16(dptr + 6);
 
-    if (!ble_ll_ctrl_chk_supp_bytes(ctrl_req.max_rx_bytes) ||
-        !ble_ll_ctrl_chk_supp_bytes(ctrl_req.max_tx_bytes) ||
-        !ble_ll_ctrl_chk_supp_time(ctrl_req.max_tx_time) ||
-        !ble_ll_ctrl_chk_supp_time(ctrl_req.max_rx_time)) {
+    if ((ctrl_req.max_rx_bytes < BLE_LL_CONN_SUPP_BYTES_MIN) ||
+        (ctrl_req.max_rx_time < BLE_LL_CONN_SUPP_TIME_MIN) ||
+        (ctrl_req.max_tx_bytes < BLE_LL_CONN_SUPP_BYTES_MIN) ||
+        (ctrl_req.max_tx_time < BLE_LL_CONN_SUPP_TIME_MIN)) {
         rc = 1;
     } else {
         /* Update the connection with the new parameters */
@@ -2228,11 +2199,14 @@ ble_ll_ctrl_rx_pdu(struct ble_ll_conn_sm *connsm, struct os_mbuf *om)
     case BLE_LL_CTRL_LENGTH_RSP:
         /* According to specification, process this only if we asked for it. */
         if (connsm->cur_ctrl_proc == BLE_LL_CTRL_PROC_DATA_LEN_UPD) {
-            /* Process the received data */
+            /*
+             * Process the received data. If received data is invalid, we'll
+             * reply with LL_UNKNOWN_RSP as per spec, but we still need to stop
+             * control procedure to avoid timeout.
+             */
             if (ble_ll_ctrl_len_proc(connsm, dptr)) {
                 rc = -1;
                 rsp_opcode = BLE_LL_CTRL_UNKNOWN_RSP;
-                goto ll_ctrl_send_rsp;
             }
 
             /* Stop the control procedure */
diff --git a/nimble/include/nimble/hci_common.h b/nimble/include/nimble/hci_common.h
index 4dd779b44..482889d7f 100644
--- a/nimble/include/nimble/hci_common.h
+++ b/nimble/include/nimble/hci_common.h
@@ -420,7 +420,7 @@ extern "C" {
 #define BLE_HCI_SET_DATALEN_TX_OCTETS_MIN   (0x001b)
 #define BLE_HCI_SET_DATALEN_TX_OCTETS_MAX   (0x00fb)
 #define BLE_HCI_SET_DATALEN_TX_TIME_MIN     (0x0148)
-#define BLE_HCI_SET_DATALEN_TX_TIME_MAX     (0x0848)
+#define BLE_HCI_SET_DATALEN_TX_TIME_MAX     (0x4290)
 
 /* --- LE read suggested default data length (OCF 0x0023) */
 #define BLE_HCI_RD_SUGG_DATALEN_RSPLEN      (4)