diff --git a/examples/nanocoap_server/coap_handler.c b/examples/nanocoap_server/coap_handler.c
index 1e827561c953..af1ac111b8b8 100644
--- a/examples/nanocoap_server/coap_handler.c
+++ b/examples/nanocoap_server/coap_handler.c
@@ -55,19 +55,19 @@ static ssize_t _riot_block2_handler(coap_pkt_t *pkt, coap_build_pkt_t *response,
     *response->cur++ = 0xff;
 
     /* Add actual content */
-    response->cur += coap_blockwise_put_bytes(&slicer, response->cur, block2_intro, sizeof(block2_intro)-1);
-    response->cur += coap_blockwise_put_bytes(&slicer, response->cur, (uint8_t*)RIOT_VERSION, strlen(RIOT_VERSION));
-    response->cur += coap_blockwise_put_char(&slicer, response->cur, ')');
-    response->cur += coap_blockwise_put_bytes(&slicer, response->cur, block2_board, sizeof(block2_board)-1);
-    response->cur += coap_blockwise_put_bytes(&slicer, response->cur, (uint8_t*)RIOT_BOARD, strlen(RIOT_BOARD));
-    response->cur += coap_blockwise_put_bytes(&slicer, response->cur, block2_mcu, sizeof(block2_mcu)-1);
-    response->cur += coap_blockwise_put_bytes(&slicer, response->cur, (uint8_t*)RIOT_MCU, strlen(RIOT_MCU));
+    coap_blockwise_put_bytes(&slicer, response, block2_intro, sizeof(block2_intro)-1);
+    coap_blockwise_put_bytes(&slicer, response, (uint8_t*)RIOT_VERSION, strlen(RIOT_VERSION));
+    coap_blockwise_put_char(&slicer, response, ')');
+    coap_blockwise_put_bytes(&slicer, response, block2_board, sizeof(block2_board)-1);
+    coap_blockwise_put_bytes(&slicer, response, (uint8_t*)RIOT_BOARD, strlen(RIOT_BOARD));
+    coap_blockwise_put_bytes(&slicer, response, block2_mcu, sizeof(block2_mcu)-1);
+    coap_blockwise_put_bytes(&slicer, response, (uint8_t*)RIOT_MCU, strlen(RIOT_MCU));
     /* To demonstrate individual chars */
-    response->cur += coap_blockwise_put_char(&slicer, response->cur, ' ');
-    response->cur += coap_blockwise_put_char(&slicer, response->cur, 'M');
-    response->cur += coap_blockwise_put_char(&slicer, response->cur, 'C');
-    response->cur += coap_blockwise_put_char(&slicer, response->cur, 'U');
-    response->cur += coap_blockwise_put_char(&slicer, response->cur, '.');
+    coap_blockwise_put_char(&slicer, response, ' ');
+    coap_blockwise_put_char(&slicer, response, 'M');
+    coap_blockwise_put_char(&slicer, response, 'C');
+    coap_blockwise_put_char(&slicer, response, 'U');
+    coap_blockwise_put_char(&slicer, response, '.');
 
     return coap_block2_build_reply(pkt, COAP_CODE_205, response, &slicer);
 }
diff --git a/sys/include/net/nanocoap.h b/sys/include/net/nanocoap.h
index 32a8e841750f..ea6db6438c64 100644
--- a/sys/include/net/nanocoap.h
+++ b/sys/include/net/nanocoap.h
@@ -823,14 +823,14 @@ void coap_block_slicer_init(coap_block_slicer_t *slicer, size_t blknum,
  * parts that are outside the current block2 request.
  *
  * @param[in]   slicer      slicer to use
- * @param[in]   bufpos      pointer to the current payload buffer position
+ * @param[out]  pkt         destination packet
  * @param[in]   c           byte array to copy
  * @param[in]   len         length of the byte array
  *
  * @returns     Number of bytes written to @p bufpos
  */
-size_t coap_blockwise_put_bytes(coap_block_slicer_t *slicer, uint8_t *bufpos,
-                                const uint8_t *c, size_t len);
+size_t coap_blockwise_put_bytes(coap_block_slicer_t *slicer, coap_build_pkt_t *pkt,
+                                const void *c, size_t len);
 
 /**
  * @brief Add a single character to a block2 reply.
@@ -840,12 +840,12 @@ size_t coap_blockwise_put_bytes(coap_block_slicer_t *slicer, uint8_t *bufpos,
  * when the character is outside the current block2 request.
  *
  * @param[in]   slicer      slicer to use
- * @param[in]   bufpos      pointer to the current payload buffer position
+ * @param[out]  pkt         destination packet
  * @param[in]   c           character to write
  *
  * @returns     Number of bytes written to @p bufpos
  */
-size_t coap_blockwise_put_char(coap_block_slicer_t *slicer, uint8_t *bufpos, char c);
+size_t coap_blockwise_put_char(coap_block_slicer_t *slicer, coap_build_pkt_t *pkt, char c);
 
 /**
  * @brief    Block option getter
diff --git a/sys/net/application_layer/nanocoap/nanocoap.c b/sys/net/application_layer/nanocoap/nanocoap.c
index ccc3864f710b..2fb907c840f6 100644
--- a/sys/net/application_layer/nanocoap/nanocoap.c
+++ b/sys/net/application_layer/nanocoap/nanocoap.c
@@ -1061,11 +1061,11 @@ ssize_t coap_block2_build_reply(coap_pkt_t *pkt, unsigned code,
     return coap_build_reply(pkt, code, response);
 }
 
-size_t coap_blockwise_put_char(coap_block_slicer_t *slicer, uint8_t *bufpos, char c)
+size_t coap_blockwise_put_char(coap_block_slicer_t *slicer, coap_build_pkt_t *pkt, char c)
 {
     /* Only copy the char if it is within the window */
     if ((slicer->start <= slicer->cur) && (slicer->cur < slicer->end)) {
-        *bufpos = c;
+        *pkt->cur++ = c;
         slicer->cur++;
         return 1;
     }
@@ -1073,8 +1073,8 @@ size_t coap_blockwise_put_char(coap_block_slicer_t *slicer, uint8_t *bufpos, cha
     return 0;
 }
 
-size_t coap_blockwise_put_bytes(coap_block_slicer_t *slicer, uint8_t *bufpos,
-                                const uint8_t *c, size_t len)
+size_t coap_blockwise_put_bytes(coap_block_slicer_t *slicer, coap_build_pkt_t *pkt,
+                                const void *c, size_t len)
 {
     size_t str_len = 0;    /* Length of the string to copy */
 
@@ -1097,8 +1097,10 @@ size_t coap_blockwise_put_bytes(coap_block_slicer_t *slicer, uint8_t *bufpos,
     }
 
     /* Only copy the relevant part of the string to the buffer */
-    memcpy(bufpos, c + str_offset, str_len);
+    memcpy(pkt->cur, (const uint8_t *)c + str_offset, str_len);
     slicer->cur += len;
+    pkt->cur += str_len;
+
     return str_len;
 }
 
@@ -1115,13 +1117,12 @@ ssize_t coap_well_known_core_default_handler(coap_pkt_t *pkt, coap_build_pkt_t *
 
     for (unsigned i = 0; i < coap_resources_numof; i++) {
         if (i) {
-            response->cur += coap_blockwise_put_char(&slicer, response->cur, ',');
+            coap_blockwise_put_char(&slicer, response, ',');
         }
-        response->cur += coap_blockwise_put_char(&slicer, response->cur, '<');
         unsigned url_len = strlen(coap_resources[i].path);
-        response->cur += coap_blockwise_put_bytes(&slicer, response->cur,
-                (uint8_t*)coap_resources[i].path, url_len);
-        response->cur += coap_blockwise_put_char(&slicer, response->cur, '>');
+        coap_blockwise_put_char(&slicer, response, '<');
+        coap_blockwise_put_bytes(&slicer, response, coap_resources[i].path, url_len);
+        coap_blockwise_put_char(&slicer, response, '>');
     }
 
     return coap_block2_build_reply(pkt, COAP_CODE_205, response, &slicer);