diff --git a/engine/events/battle_tower/load_trainer.asm b/engine/events/battle_tower/load_trainer.asm
index 67c9d2232..c84020e9d 100644
--- a/engine/events/battle_tower/load_trainer.asm
+++ b/engine/events/battle_tower/load_trainer.asm
@@ -27,12 +27,12 @@ Function_LoadOpponentTrainerAndPokemons: ; 1f8000
 	add b
 	ld b, a ; b contains the nr of the trainer
 if DEF(_CRYSTAL11)
-	maskbits BATTLETOWER_NUM_UNIQUE_TRAINERS
+	maskbits BATTLETOWER_NUM_UNIQUE_TRAINERS +- 1
 	cp BATTLETOWER_NUM_UNIQUE_TRAINERS
 else
 ; Crystal 1.0 used the wrong constant here, so only the first 21
 ; trainers in BattleTowerTrainers can be sampled.
-	maskbits BATTLETOWER_NUM_UNIQUE_PKMN
+	maskbits BATTLETOWER_NUM_UNIQUE_PKMN +- 1
 	cp BATTLETOWER_NUM_UNIQUE_PKMN
 endc
 	jr nc, .resample
@@ -115,7 +115,7 @@ Function_LoadRandomBattleTowerPkmn: ; 1f8081
 	ld a, [hRandomAdd]
 	add b
 	ld b, a
-	maskbits BATTLETOWER_NUM_UNIQUE_PKMN
+	maskbits BATTLETOWER_NUM_UNIQUE_PKMN +- 1
 	cp BATTLETOWER_NUM_UNIQUE_PKMN
 	jr nc, .resample
 	; in register 'a' is the chosen Pkmn of the LevelGroup
diff --git a/home/time.asm b/home/time.asm
index 9ed703686..be141a066 100644
--- a/home/time.asm
+++ b/home/time.asm
@@ -48,17 +48,17 @@ GetClock:: ; 5b7
 
 	ld [hl], RTC_S
 	ld a, [de]
-	maskbits 60
+	maskbits 60 - 1
 	ld [hRTCSeconds], a
 
 	ld [hl], RTC_M
 	ld a, [de]
-	maskbits 60
+	maskbits 60 - 1
 	ld [hRTCMinutes], a
 
 	ld [hl], RTC_H
 	ld a, [de]
-	maskbits 24
+	maskbits 24 - 1
 	ld [hRTCHours], a
 
 	ld [hl], RTC_DL