diff --git a/sys/include/net/nanocoap.h b/sys/include/net/nanocoap.h
index f8fdd7a5e3..1091fc4df0 100644
--- a/sys/include/net/nanocoap.h
+++ b/sys/include/net/nanocoap.h
@@ -366,7 +366,7 @@ static inline unsigned coap_get_code(const coap_pkt_t *pkt)
  *
  * @returns     raw message code
  */
-static inline unsigned coap_get_code_raw(coap_pkt_t *pkt)
+static inline unsigned coap_get_code_raw(const coap_pkt_t *pkt)
 {
     return (unsigned)pkt->hdr->code;
 }
@@ -378,7 +378,7 @@ static inline unsigned coap_get_code_raw(coap_pkt_t *pkt)
  *
  * @returns     message ID
  */
-static inline unsigned coap_get_id(coap_pkt_t *pkt)
+static inline unsigned coap_get_id(const coap_pkt_t *pkt)
 {
     return ntohs(pkt->hdr->id);
 }
@@ -429,7 +429,7 @@ static inline unsigned coap_get_total_len(const coap_pkt_t *pkt)
  * @returns     COAP_TYPE_ACK
  * @returns     COAP_TYPE_RST
  */
-static inline unsigned coap_get_type(coap_pkt_t *pkt)
+static inline unsigned coap_get_type(const coap_pkt_t *pkt)
 {
     return (pkt->hdr->ver_t_tkl & 0x30) >> 4;
 }
@@ -441,7 +441,7 @@ static inline unsigned coap_get_type(coap_pkt_t *pkt)
  *
  * @returns     CoAP version number
  */
-static inline unsigned coap_get_ver(coap_pkt_t *pkt)
+static inline unsigned coap_get_ver(const coap_pkt_t *pkt)
 {
     return (pkt->hdr->ver_t_tkl & 0x60) >> 6;
 }
@@ -453,7 +453,7 @@ static inline unsigned coap_get_ver(coap_pkt_t *pkt)
  *
  * @returns     pointer to first byte after the header
  */
-static inline uint8_t *coap_hdr_data_ptr(coap_hdr_t *hdr)
+static inline uint8_t *coap_hdr_data_ptr(const coap_hdr_t *hdr)
 {
     return ((uint8_t *)hdr) + sizeof(coap_hdr_t);
 }
diff --git a/sys/net/application_layer/nanocoap/nanocoap.c b/sys/net/application_layer/nanocoap/nanocoap.c
index bc04d68bb9..290e91bef3 100644
--- a/sys/net/application_layer/nanocoap/nanocoap.c
+++ b/sys/net/application_layer/nanocoap/nanocoap.c
@@ -812,13 +812,12 @@ size_t coap_opt_put_uri_pathquery(uint8_t *buf, uint16_t *lastonum, const char *
     size_t bytes_out = coap_opt_put_string_with_len(buf, *lastonum,
                                                     COAP_OPT_URI_PATH,
                                                     uri, len, '/');
-
     if (query) {
         buf += bytes_out;
         bytes_out += coap_opt_put_uri_query(buf, COAP_OPT_URI_PATH, query + 1);
         *lastonum = COAP_OPT_URI_QUERY;
     }
-    else {
+    else if (bytes_out) {
         *lastonum = COAP_OPT_URI_PATH;
     }
 
diff --git a/sys/net/application_layer/nanocoap/sock.c b/sys/net/application_layer/nanocoap/sock.c
index da72be37f4..1dc27d4a71 100644
--- a/sys/net/application_layer/nanocoap/sock.c
+++ b/sys/net/application_layer/nanocoap/sock.c
@@ -25,9 +25,11 @@
 #include <string.h>
 #include <stdio.h>
 
+#include "atomic_utils.h"
 #include "net/nanocoap_sock.h"
 #include "net/sock/util.h"
 #include "net/sock/udp.h"
+#include "random.h"
 #include "sys/uio.h"
 #include "timex.h"
 
@@ -45,6 +47,13 @@ typedef struct {
     bool more;
 } _block_ctx_t;
 
+static uint16_t _get_id(void)
+{
+    __attribute__((section(".noinit")))
+    static uint16_t id;
+    return atomic_fetch_add_u16(&id, 1);
+}
+
 int nanocoap_sock_connect(nanocoap_sock_t *sock, sock_udp_ep_t *local, sock_udp_ep_t *remote)
 {
     if (!remote->port) {
@@ -88,9 +97,8 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
 
     unsigned state = STATE_SEND_REQUEST;
 
-    /* TODO: timeout random between between ACK_TIMEOUT and (ACK_TIMEOUT * ACK_RANDOM_FACTOR) */
-    uint32_t timeout = CONFIG_COAP_ACK_TIMEOUT_MS * US_PER_MS;
-
+    uint32_t timeout = random_uint32_range(CONFIG_COAP_ACK_TIMEOUT_MS * US_PER_MS,
+                                           CONFIG_COAP_ACK_TIMEOUT_MS * CONFIG_COAP_RANDOM_FACTOR_1000);
     /* add 1 for initial transmit */
     unsigned tries_left = CONFIG_COAP_MAX_RETRANSMIT + 1;
 
@@ -127,7 +135,6 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
             if (res == -ETIMEDOUT) {
                 DEBUG("nanocoap: timeout\n");
                 timeout *= 2;
-                tries_left--;
                 state = STATE_SEND_REQUEST;
                 continue;
             }
@@ -231,7 +238,7 @@ ssize_t nanocoap_sock_get(nanocoap_sock_t *sock, const char *path, void *buf, si
     };
 
     pkt.hdr = buf;
-    pktpos += coap_build_hdr(pkt.hdr, COAP_TYPE_CON, NULL, 0, COAP_METHOD_GET, 1);
+    pktpos += coap_build_hdr(pkt.hdr, COAP_TYPE_CON, NULL, 0, COAP_METHOD_GET, _get_id());
     pktpos += coap_opt_put_uri_path(pktpos, 0, path);
     pkt.payload = pktpos;
     pkt.payload_len = 0;
@@ -309,8 +316,7 @@ static int _fetch_block(coap_pkt_t *pkt, sock_udp_t *sock,
     uint8_t *pktpos = (void *)pkt->hdr;
     uint16_t lastonum = 0;
 
-    pktpos += coap_build_hdr(pkt->hdr, COAP_TYPE_CON, NULL, 0, COAP_METHOD_GET,
-                             num);
+    pktpos += coap_build_hdr(pkt->hdr, COAP_TYPE_CON, NULL, 0, COAP_METHOD_GET, _get_id());
     pktpos += coap_opt_put_uri_pathquery(pktpos, &lastonum, path);
     pktpos += coap_opt_put_uint(pktpos, lastonum, COAP_OPT_BLOCK2,
                                 (num << 4) | blksize);