diff --git a/firmware/ice40-riscv/icE1usb/e1.c b/firmware/ice40-riscv/icE1usb/e1.c
index 6a87c12..f25e7c1 100644
--- a/firmware/ice40-riscv/icE1usb/e1.c
+++ b/firmware/ice40-riscv/icE1usb/e1.c
@@ -273,8 +273,8 @@
 	memset(e1, 0x00, sizeof(struct e1_state));
 
 	/* Reset FIFOs */
-	e1f_reset(&e1->rx.fifo, (256 * port) +   0, 128);
-	e1f_reset(&e1->tx.fifo, (256 * port) + 128, 128);
+	e1f_reset(&e1->rx.fifo, (512 * port) +   0, 256);
+	e1f_reset(&e1->tx.fifo, (512 * port) + 256, 256);
 
 	/* Enable Rx */
 	e1->rx.cr = E1_RX_CR_ENABLE | rx_cr;