diff --git a/firmware/ice40-riscv/icE1usb/e1.c b/firmware/ice40-riscv/icE1usb/e1.c
index 5d4d3ee..0f1d89d 100644
--- a/firmware/ice40-riscv/icE1usb/e1.c
+++ b/firmware/ice40-riscv/icE1usb/e1.c
@@ -328,7 +328,7 @@
 #include "dma.h"
 
 unsigned int
-e1_rx_need_data(unsigned int usb_addr, unsigned int max_frames)
+e1_rx_need_data(unsigned int usb_addr, unsigned int max_frames, unsigned int *pos)
 {
 	unsigned int ofs;
 	int tot_frames = 0;
@@ -340,6 +340,12 @@
 		if (!n_frames)
 			break;
 
+		/* Give pos */
+		if (pos) {
+			*pos = ofs & g_e1.rx.fifo.mask;
+			pos = NULL;
+		}
+
 		/* Copy from FIFO to USB */
 		dma_exec(e1f_ofs_to_dma(ofs), usb_addr, n_frames * (32 / 4), false, NULL, NULL);