diff --git a/LTTP_RND_GeneralBugfixes.asm b/LTTP_RND_GeneralBugfixes.asm
index b489c08..466b57a 100644
--- a/LTTP_RND_GeneralBugfixes.asm
+++ b/LTTP_RND_GeneralBugfixes.asm
@@ -478,6 +478,15 @@ Sprite_CheckIfPlayerPreoccupied:
 org $08C3AE
 Ancilla_ReceiveItem:
 
+org $08CE93
+Ancilla_BreakTowerSeal_draw_single_crystal:
+
+org $08CEC3
+Ancilla_BreakTowerSeal_stop_spawning_sparkles:
+
+org $08CF59
+BreakTowerSeal_ExecuteSparkles:
+
 org $08F710
 Ancilla_SetOam_XY_Long:
 
diff --git a/entrances.asm b/entrances.asm
index b84417d..96149b0 100644
--- a/entrances.asm
+++ b/entrances.asm
@@ -12,8 +12,11 @@ LockAgahnimDoors:
 			JSR.w LockAgahnimDoorsCore : RTL
 	+ : CMP.w #$0002 : BNE +
 		JSR.w LockAgahnimDoorsCore : BEQ .unlock
-		LDA $7EF37A : AND.w #$007F : CMP.w #$007F : BEQ .crystalOrUnlock
-			LDA #$0001 : RTL
+		SEP #$30
+		JSL.l CheckEnoughCrystals
+		REP #$30
+		BEQ .crystalOrUnlock
+		LDA #$0001 : RTL
 		.crystalOrUnlock
 		LDA InvertedMode : AND.w #$00FF : BEQ .unlock
 
diff --git a/goalitem.asm b/goalitem.asm
index 6f5765f..5259fb2 100644
--- a/goalitem.asm
+++ b/goalitem.asm
@@ -46,7 +46,43 @@ CheckGanonVulnerability:
 		;#$05 = Require 100 Goal Items
 		LDA.l !GOAL_COUNTER : CMP.b #100 : !BLT .fail ; require 100 goal items
 		BRA .success
+	+ : CMP #$06 : BNE +
+		;#$06 = Require "NumberOfCrystalsRequired" Crystals
+		JSR CheckEnoughCrystals : BCC .fail
+		BRA .success
 	+
 .fail : CLC : RTL
 .success : SEC : RTL
-;--------------------------------------------------------------------------------
\ No newline at end of file
+;--------------------------------------------------------------------------------
+GetRequriedCrystals:
+	BEQ + : JSL.l BreakTowerSeal_ExecuteSparkles : + ; thing we wrote over
+	LDA.l NumberOfCrystalsRequired : CMP.b #$00 : BNE + : JML.l Ancilla_BreakTowerSeal_stop_spawning_sparkles : +
+	LDA.l NumberOfCrystalsRequired : CMP.b #$01 : BNE + : JML.l Ancilla_BreakTowerSeal_draw_single_crystal : +
+	LDA.l NumberOfCrystalsRequired : DEC #2 : TAX
+JML.l GetRequriedCrystals_continue
+;--------------------------------------------------------------------------------
+GetRequriedCrystalsInX:
+	LDA.l NumberOfCrystalsRequired : CMP.b #$00 : BNE +
+		TAX
+		RTL
+	+
+	
+	TXA : - : CMP.l NumberOfCrystalsRequired : !BLT + : !SUB.l NumberOfCrystalsRequired : BRA - : +
+	
+	INC : CMP.l NumberOfCrystalsRequired : BNE +
+		LDA.b #$08
+	+ : DEC : TAX
+RTL
+;--------------------------------------------------------------------------------
+CheckEnoughCrystals:
+	LDA InvincibleGanon : CMP #$06 : BNE .normal
+	.other
+	PHX : PHY
+	LDA $7EF37A : JSL CountBits ; the comparison is against 1 less
+	PLY : PLX
+	CMP.l NumberOfCrystalsRequired
+RTL
+
+	.normal
+	LDA $7EF37A : AND.b #$7F : CMP.b #$7F ; thing we wrote over
+RTL
\ No newline at end of file
diff --git a/hooks.asm b/hooks.asm
index e67feeb..8011b52 100755
--- a/hooks.asm
+++ b/hooks.asm
@@ -323,6 +323,25 @@ org $1BBD77 ; <- bank1B.asm : 308 (SEP #$30)
 PreventEnterOnBonk_BRANCH_IX:
 ;--------------------------------------------------------------------------------
 
+;================================================================================
+; Crystals Mode
+;--------------------------------------------------------------------------------
+org $099B7B ; <- ancilla_init.asm : 4136 (LDA $7EF37A : AND.b #$7F : CMP.b #$7F)
+JSL.l CheckEnoughCrystals
+NOP #4
+db #$90 ; BCC
+;--------------------------------------------------------------------------------
+org $08CE0C ; <- 44E0C - ancilla_break_tower_seal.asm : 168 (BEQ #$03 : JSR BreakTowerSeal_ExecuteSparkles : LDX.b #$06)
+JML.l GetRequriedCrystals
+NOP #3
+GetRequriedCrystals_continue:
+;--------------------------------------------------------------------------------
+org $08CF19 ; <- 44F19 - ancilla_break_tower_seal.asm : 336 (TXA : AND.b #$07 : TAX)
+JSL.l GetRequriedCrystalsInX
+;--------------------------------------------------------------------------------
+org $08CFC9 ; <- 44FC9 - ancilla_break_tower_seal.asm : 414 (RTS)
+db #$6B
+;--------------------------------------------------------------------------------
 
 ;================================================================================
 ; Hash Key Display
diff --git a/tables.asm b/tables.asm
index 1c89fb8..761ac66 100644
--- a/tables.asm
+++ b/tables.asm
@@ -153,6 +153,7 @@ db #$00
 ; #$03 = Require Crystals and Aga2
 ; #$04 = Require Crystals
 ; #$05 = Require 100 Goal Items
+; #$06 = Require "NumberOfCrystalsRequired"
 ;--------------------------------------------------------------------------------
 org $30803F ; PC 0x18003F
 HammerableGanon:
@@ -255,7 +256,11 @@ CrystalPendantFlags_2:
 ;Pendant: $00
 ;Crystal: $40
 ;--------------------------------------------------------------------------------
-; 0x18005E - 0x18005F (unused)
+org $30805E ; PC 0x18005E - Number of crystals required to enter GT
+NumberOfCrystalsRequired:
+db #$07 ; #$07 = 7 Crystals
+;--------------------------------------------------------------------------------
+; 0x18005F - 0x18005F (unused)
 ;--------------------------------------------------------------------------------
 org $308060 ; PC 0x180060 - 0x18007E
 ProgrammableItemLogicJump_1:
diff --git a/utilities.asm b/utilities.asm
index a806d02..c12da75 100644
--- a/utilities.asm
+++ b/utilities.asm
@@ -593,6 +593,29 @@ HexToDec:
 	PLA
 RTL
 
+;--------------------------------------------------------------------------------
+; CountBits
+; in: A(b) - Byte to count bits in
+; out: A(b) - sum of bits
+; caller is responsible for setting 8-bit mode and preserving X and Y
+;--------------------------------------------------------------------------------
+CountBits:
+	PHB : PHK : PLB
+	TAX                     ; Save a copy of value
+	LSR #4                  ; Shift down hi nybble, Leave <3> in C
+	TAY                     ; And save <7:4> in Y
+	TXA                     ; Recover value
+	AND #$07                ; Put out <2:0> in X
+	TAX                     ; And save in X
+	LDA NybbleBitCounts, Y  ; Fetch count for Y
+	ADC NybbleBitCounts, X  ; Add count for X & C
+	PLB
+RTL
+
+; Look up table of bit counts in the values $00-$0F
+NybbleBitCounts:
+db #00, #01, #01, #02, #01, #02, #02, #03, #01, #02, #02, #03, #02, #03, #03, #04
+
 ;--------------------------------------------------------------------------------
 
 ;--------------------------------------------------------------------------------