diff --git a/doc/fixes35.0 b/doc/fixes35.0
index 118ba60c8..8aef6e126 100644
--- a/doc/fixes35.0
+++ b/doc/fixes35.0
@@ -848,6 +848,8 @@ entering an untended shop while blind gave an inappropriate message
 engraving feedback about partial text when weapon became too dull to finish
 	was lacking sentence-ending period
 impossible() might display inaccurate feedback after updating paniclog
+fix crash which occurred if hero was teleported onto a sink while busy putting
+	on or taking off levitation boots
 
 
 Platform- and/or Interface-Specific Fixes
diff --git a/src/hack.c b/src/hack.c
index 055930d9f..728e75774 100644
--- a/src/hack.c
+++ b/src/hack.c
@@ -497,9 +497,13 @@ dosinkfall()
 {
 	register struct obj *obj;
 	int dmg;
+	boolean lev_boots = (uarmf && uarmf->otyp == LEVITATION_BOOTS),
+		innate_lev = ((HLevitation & (FROMOUTSIDE|FROMFORM)) != 0L),
+        	ufall = (!innate_lev && !(HFlying || EFlying)); /* BFlying */
 
-	if (HLevitation & (FROMOUTSIDE|FROMFORM)) {
-	    You("wobble unsteadily for a moment.");
+	if (!ufall) {
+	    You(innate_lev ? "wobble unsteadily for a moment." :
+			     "gain control of your flight.");
 	} else {
 	    long save_ELev = ELevitation, save_HLev = HLevitation;
 
@@ -524,6 +528,25 @@ dosinkfall()
 	    HLevitation = save_HLev;
 	}
 
+	/*
+	 * Interrupt multi-turn putting on/taking off of armor (in which
+	 * case we reached the sink due to being teleported while busy;
+	 * in 3.4.3, Boots_on()/Boots_off() [called via (*aftermv)() when
+	 * 'multi' reaches 0] triggered a crash if we were donning/doffing
+	 * levitation boots [because the Boots_off() below causes 'uarmf'
+	 * to be null by the time 'aftermv' gets called]).
+	 *
+	 * Interrupt donning/doffing if we fall onto the sink, or if the
+	 * code below is going to remove levitation boots even when we
+	 * haven't fallen (innate floating or flying becoming unblocked).
+	 */
+	if (ufall || lev_boots) {
+	    (void) stop_donning(lev_boots ? uarmf :  (struct obj *)0);
+	    /* recalculate in case uarmf just got set to null */
+	    lev_boots = (uarmf && uarmf->otyp == LEVITATION_BOOTS);
+	}
+
+	/* remove worn levitation items */
 	ELevitation &= ~W_ARTI;
 	HLevitation &= ~(I_SPECIAL|TIMEOUT);
 	HLevitation++;
@@ -537,7 +560,7 @@ dosinkfall()
 	    Ring_off(obj);
 	    off_msg(obj);
 	}
-	if(uarmf && uarmf->otyp == LEVITATION_BOOTS) {
+	if (lev_boots) {
 	    obj = uarmf;
 	    (void)Boots_off();
 	    off_msg(obj);