diff --git a/tools/atrf-proxy/atrf-proxy.c b/tools/atrf-proxy/atrf-proxy.c
index fbdf344..f860255 100644
--- a/tools/atrf-proxy/atrf-proxy.c
+++ b/tools/atrf-proxy/atrf-proxy.c
@@ -176,8 +176,6 @@ static int cmd_more(struct atrf_dsc *dsc, struct netio *netio, const char *cmd)
 		res = atrf_interrupt_wait(dsc, n);
 		if (atrf_error(dsc))
 			return netio_printf(netio, "-I/O error\n");
-		if (res < 0)
-			return netio_printf(netio, "-not supported\n");
 		return netio_printf(netio, "+0x%02x\n", res);
 	}
 	if (!strcasecmp(cmd, "getram")) {
diff --git a/tools/lib/atrf.c b/tools/lib/atrf.c
index 15f1b07..57371e4 100644
--- a/tools/lib/atrf.c
+++ b/tools/lib/atrf.c
@@ -320,6 +320,5 @@ uint8_t atrf_sram_read(struct atrf_dsc *dsc, uint8_t addr)
 
 int atrf_interrupt_wait(struct atrf_dsc *dsc, int timeout_ms)
 {
-	return dsc->driver->interrupt_wait ?
-	    dsc->driver->interrupt_wait(dsc->handle, timeout_ms) : -1;
+	return dsc->driver->interrupt_wait(dsc->handle, timeout_ms);
 }
diff --git a/tools/lib/atusb-common.c b/tools/lib/atusb-common.c
index bcb588e..6766eda 100644
--- a/tools/lib/atusb-common.c
+++ b/tools/lib/atusb-common.c
@@ -221,8 +221,7 @@ int atusb_interrupt_wait(void *handle, int timeout_ms)
 		if (res < 0) {
 			fprintf(stderr, "usb_bulk_read: %d\n", res);
 			dsc->error = 1;
-			return 0;
-			    /* < 0 is already taken by atrf_interrupt_wait */
+			return 0; /* handle this via atrf_error */
 		}
 		timeout_ms = 1;
 		for (i = 0; i != res; i++)