diff --git a/hardware/agilent-dmm/sched.c b/hardware/agilent-dmm/sched.c
index 140c5340..5ae73aca 100644
--- a/hardware/agilent-dmm/sched.c
+++ b/hardware/agilent-dmm/sched.c
@@ -89,7 +89,7 @@ static void receive_line(const struct sr_dev_inst *sdi)
 
 SR_PRIV int agdmm_receive_data(int fd, int revents, void *cb_data)
 {
-	const struct sr_dev_inst *sdi;
+	struct sr_dev_inst *sdi;
 	struct dev_context *devc;
 	int len;
 
diff --git a/hardware/fluke-dmm/fluke.c b/hardware/fluke-dmm/fluke.c
index f8544e99..dadcc495 100644
--- a/hardware/fluke-dmm/fluke.c
+++ b/hardware/fluke-dmm/fluke.c
@@ -307,7 +307,7 @@ static void handle_line(const struct sr_dev_inst *sdi)
 
 SR_PRIV int fluke_receive_data(int fd, int revents, void *cb_data)
 {
-	const struct sr_dev_inst *sdi;
+	struct sr_dev_inst *sdi;
 	struct dev_context *devc;
 	int len;
 	int64_t now, elapsed;
diff --git a/hardware/radioshack-dmm/radioshack.c b/hardware/radioshack-dmm/radioshack.c
index 64ef59be..67460308 100644
--- a/hardware/radioshack-dmm/radioshack.c
+++ b/hardware/radioshack-dmm/radioshack.c
@@ -391,7 +391,7 @@ static void handle_new_data(rs_dev_ctx *devc, int fd)
 
 SR_PRIV int radioshack_receive_data(int fd, int revents, void *cb_data)
 {
-	const struct sr_dev_inst *sdi;
+	struct sr_dev_inst *sdi;
 	struct dev_context *devc;
 
 	if (!(sdi = cb_data))
diff --git a/hardware/tekpower-dmm/protocol.c b/hardware/tekpower-dmm/protocol.c
index 87f83c15..2d495f1a 100644
--- a/hardware/tekpower-dmm/protocol.c
+++ b/hardware/tekpower-dmm/protocol.c
@@ -104,7 +104,7 @@ static void handle_new_data(struct dev_context *devc, int fd)
 
 SR_PRIV int tekpower_dmm_receive_data(int fd, int revents, void *cb_data)
 {
-	const struct sr_dev_inst *sdi;
+	struct sr_dev_inst *sdi;
 	struct dev_context *devc;
 
 	if (!(sdi = cb_data))