Index: sys/dev/mmc/mmc.c
===================================================================
--- sys/dev/mmc/mmc.c
+++ sys/dev/mmc/mmc.c
@@ -958,17 +958,32 @@
 mmc_set_vccq(struct mmc_softc *sc, struct mmc_ivars *ivar,
     enum mmc_bus_timing timing)
 {
-
-	if (isset(&ivar->vccq_120, timing))
+	if (isset(&ivar->vccq_120, timing)) {
 		mmcbr_set_vccq(sc->dev, vccq_120);
-	else if (isset(&ivar->vccq_180, timing))
+		if (mmcbr_switch_vccq(sc->dev) == 0)
+			return (MMC_ERR_NONE);
+
+		/* Failed to switch to 1.2V, disabling it for this timing */
+		clrbit(&ivar->vccq_120, timing);
+	}
+
+	if (isset(&ivar->vccq_180, timing)) {
 		mmcbr_set_vccq(sc->dev, vccq_180);
-	else
+		if (mmcbr_switch_vccq(sc->dev) == 0)
+			return (MMC_ERR_NONE);
+		
+		/* Failed to switch to 1.8V, disabling it for this timing */
+		clrbit(&ivar->vccq_180, timing);
+	}
+	
+	if (timing == bus_timing_normal || timing == bus_timing_hs) {
+		/* Only these two run on 3.3V */
 		mmcbr_set_vccq(sc->dev, vccq_330);
-	if (mmcbr_switch_vccq(sc->dev) != 0)
-		return (MMC_ERR_INVALID);
-	else
-		return (MMC_ERR_NONE);
+		if (mmcbr_switch_vccq(sc->dev) == 0)
+			return (MMC_ERR_NONE);
+	}
+
+	return (MMC_ERR_INVALID);
 }
 
 static const uint8_t p8[8] = {
@@ -2120,6 +2135,8 @@
 	dev = sc->dev;
 	max_dtr = mmcbr_get_f_max(dev);
 	max_timing = bus_timing_max;
+
+again:
 	do {
 		changed = false;
 		for (i = 0; i < sc->child_count; i++) {
@@ -2151,6 +2168,12 @@
 		    mmc_timing_to_string(max_timing));
 	}
 
+	/*
+	 * We deselect the card in case we failed to switch
+	 * timing in the previous try on the first card
+	 */
+	(void)mmc_select_card(sc, 0);
+
 	/*
 	 * HS400 must be tuned in HS200 mode, so in case of HS400 we begin
 	 * with HS200 following the sequence as described in "6.6.2.2 HS200
@@ -2178,7 +2201,8 @@
 			if (mmc_set_vccq(sc, ivar, timing) != MMC_ERR_NONE) {
 				device_printf(dev, "Failed to set VCCQ for "
 				    "card at relative address %d\n", rca);
-				continue;
+				max_timing = timing - 1;
+				goto again;
 			}
 		}
 
@@ -2226,7 +2250,8 @@
 			if (mmc_set_vccq(sc, ivar, timing) != MMC_ERR_NONE) {
 				device_printf(dev, "Failed to set VCCQ for "
 				    "card at relative address %d\n", rca);
-				continue;
+				max_timing = timing - 1;
+				goto again;
 			}
 		}