diff --git a/gex/gex_client.c b/gex/gex_client.c
index c4c9fba..8649d64 100644
--- a/gex/gex_client.c
+++ b/gex/gex_client.c
@@ -50,7 +50,6 @@ static TF_Result unit_report_lst(TinyFrame *tf, TF_Msg *msg)
     };
 
     GexMsg gexMsg = {
-        .session = msg->frame_id,
         .payload = (uint8_t *) (msg->data + 2),
         .len = (uint32_t) (msg->len - 2),
         .type = rpt_type,
diff --git a/gex/gex_defines.h b/gex/gex_defines.h
index d544713..1491de4 100644
--- a/gex/gex_defines.h
+++ b/gex/gex_defines.h
@@ -28,14 +28,10 @@ typedef void (*GexEventListener)(GexMsg msg);
  * Contains all needed information to lead a multi-part dialogue.
  */
 struct gex_msg {
-    GexUnit *unit;
-    uint8_t *payload;
-    uint32_t len;
-    GexSession session;
-    union {
-        uint8_t cmd;
-        uint8_t type;
-    };
+    GexUnit *unit;       //!< Unit this message belongs to
+    uint8_t *payload;    //!< Useful payload
+    uint32_t len;        //!< Payload length
+    uint8_t type;        //!< Message type (e.g. MSG_ERROR), or report type in event handler
 };
 
 /**
diff --git a/gex/gex_unit.c b/gex/gex_unit.c
index adf8b8c..f23f814 100644
--- a/gex/gex_unit.c
+++ b/gex/gex_unit.c
@@ -20,7 +20,7 @@
  * @param lst - TF listener to handle the response, can be NULL
  * @param userdata2 userdata2 argument for the TF listener's message
  */
-static void GEX_LL_Query(GexUnit *unit, uint8_t cmd, uint8_t *payload, uint32_t len, TF_Listener lst, void *userdata2)
+static void GEX_LL_Query(GexUnit *unit, uint8_t cmd, const uint8_t *payload, uint32_t len, TF_Listener lst, void *userdata2)
 {
     assert(unit != NULL);
     assert(unit->gex != NULL);
@@ -51,7 +51,7 @@ static void GEX_LL_Query(GexUnit *unit, uint8_t cmd, uint8_t *payload, uint32_t
 }
 
 /** Send with no listener, don't wait for response */
-void GEX_Send(GexUnit *unit, uint8_t cmd, uint8_t *payload, uint32_t len)
+void GEX_Send(GexUnit *unit, uint8_t cmd, const uint8_t *payload, uint32_t len)
 {
     assert(unit != NULL);
     assert(unit->gex != NULL);
@@ -67,7 +67,6 @@ static TF_Result sync_query_lst(TinyFrame *tf, TF_Msg *msg)
 
     // clone the message
     gex->sync_query_response.len = msg->len;
-    gex->sync_query_response.session = msg->frame_id;
     gex->sync_query_response.unit = msg->userdata;
     gex->sync_query_response.type = msg->type;
     // clone the buffer
@@ -78,7 +77,7 @@ static TF_Result sync_query_lst(TinyFrame *tf, TF_Msg *msg)
 }
 
 /** Static query */
-GexMsg GEX_Query(GexUnit *unit, uint8_t cmd, uint8_t *payload, uint32_t len)
+GexMsg GEX_Query(GexUnit *unit, uint8_t cmd, const uint8_t *payload, uint32_t len)
 {
     assert(unit != NULL);
     assert(unit->gex != NULL);
@@ -89,7 +88,6 @@ GexMsg GEX_Query(GexUnit *unit, uint8_t cmd, uint8_t *payload, uint32_t len)
 
     // Default response that will be used if nothing is received
     gex->sync_query_response.unit = unit;
-    gex->sync_query_response.session = 0;
     gex->sync_query_response.type = MSG_ERROR;
     sprintf((char *) gex->sync_query_buffer, "TIMEOUT");
     gex->sync_query_response.len = (uint32_t) strlen("TIMEOUT");
@@ -125,7 +123,7 @@ static TF_Result async_query_lst(TinyFrame *tf, TF_Msg *msg)
 }
 
 /** Sync query, without poll */
-void GEX_QueryAsync(GexUnit *unit, uint8_t cmd, uint8_t *payload, uint32_t len, GexEventListener lst)
+void GEX_QueryAsync(GexUnit *unit, uint8_t cmd, const uint8_t *payload, uint32_t len, GexEventListener lst)
 {
     assert(unit != NULL);
     assert(unit->gex != NULL);
diff --git a/gex/gex_unit.h b/gex/gex_unit.h
index 073fccc..ca2ef2f 100644
--- a/gex/gex_unit.h
+++ b/gex/gex_unit.h
@@ -13,14 +13,51 @@
 #include <stdint.h>
 #include <stdbool.h>
 
-/** Send with no listener, don't wait for response */
-void GEX_Send(GexUnit *unit, uint8_t cmd, uint8_t *payload, uint32_t len);
-
-/** Static query */
-GexMsg GEX_Query(GexUnit *unit, uint8_t cmd, uint8_t *payload, uint32_t len);
-
-/** Sync query, without poll */
-void GEX_QueryAsync(GexUnit *unit, uint8_t cmd, uint8_t *payload, uint32_t len, GexEventListener lst);
-
+/** Send a command with no listener */
+void GEX_Send(GexUnit *unit, uint8_t cmd, const uint8_t *payload, uint32_t len);
+
+/** Send a command with no payload or listener */
+static inline void GEX_Send0(GexUnit *unit, uint8_t cmd)
+{
+	GEX_Send(unit, cmd, NULL, 0);
+}
+
+/** Static query, send a command and wait for the response */
+GexMsg GEX_Query(GexUnit *unit, uint8_t cmd, const uint8_t *payload, uint32_t len);
+
+/** Asynchronous query with an async listener */
+void GEX_QueryAsync(GexUnit *unit, uint8_t cmd, const uint8_t *payload, uint32_t len, GexEventListener lst);
+
+
+/**
+ * Bulk read from a unit, synchronous
+ *
+ * @param unit - the unit to target
+ * @param cmd - initial request command
+ * @param payload - initial request payload
+ * @param len - initial request payload length
+ * @param buffer - destination buffer
+ * @param capacity - size of the buffer, max nr of bytes to receive
+ * @return actual number of bytes received.
+ */
+uint32_t GEX_BulkRead(GexUnit *unit, uint8_t cmd,
+                      const uint8_t *payload, uint32_t len,
+                      uint8_t *buffer, uint32_t capacity);
+
+
+/**
+ * Bulk write to a unit, synchronous
+ *
+ * @param unit - the unit to target
+ * @param cmd - initial request command
+ * @param payload - initial request payload
+ * @param len - initial request payload length
+ * @param buffer - destination buffer
+ * @param capacity - size of the buffer, max nr of bytes to receive
+ * @return true on success
+ */
+bool GEX_BulkWrite(GexUnit *unit, uint8_t cmd,
+                   const uint8_t *payload, uint32_t len,
+                   const uint8_t *buffer, uint32_t capacity);
 
 #endif //GEX_CLIENT_GEX_UNIT_H