--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -932,9 +932,9 @@ static void bgmac_chip_reset(struct bgma
 		u8 et_swtype = 0;
 		u8 sw_type = BGMAC_CHIPCTL_1_SW_TYPE_EPHY |
 			     BGMAC_CHIPCTL_1_IF_TYPE_MII;
-		char buf[2];
+		char buf[4];
 
-		if (bcm47xx_nvram_getenv("et_swtype", buf, 1) > 0) {
+		if (bcm47xx_nvram_getenv("et_swtype", buf, sizeof(buf)) > 0) {
 			if (kstrtou8(buf, 0, &et_swtype))
 				bgmac_err(bgmac, "Failed to parse et_swtype (%s)\n",
 					  buf);