Fix Dark Sanc doorframe in inverted mode

Add sandbox code for opening TR bomb entrances for inverted

entrances.asm

@@ -82,6 +82,11 @@ AllowStartFromSingleEntranceCave:
 		STA $7EC14C ; Cache the overworld area number
 		STA $7EC140 ; Cache the aux overworld area number
 
+		SEP #$20 ; set 8-bit accumulator
+		LDX $00
+		LDA.l StartingAreaOverworldDoor, X : STA.l $7F5099 ;Load overworld door
+		REP #$20 ; reset 16-bit accumulator
+
 		.done
 	PLA
 RTL

sandbox.asm

@@ -175,6 +175,13 @@ org $07AA3A : db $D0 ; residual portal?
 org $08D40C : db $D0 ; morph poof
 org $308174 : db $01 ; ER's Fix fake worlds fix. Currently needed for inverted
 
+org $1FED31 : db $0E ; pre-open open TR bomb door
+org $1FED41 : db $0E ; pre-open open TR bomb door
+
+; Write to StartingAreaOverworldDoor table to indicate the overworld door being used for
+; the single entrance spawn point
+org $308247 ; PC 0x180247
+db $00, $5A, $00, $00, $00, $00, $00
 
 
 ;org $02E849 ; Fly 1 to Sanctuary

tables.asm

@@ -925,7 +925,14 @@ org $308240 ; PC 0x180240
 StartingAreaExitOffset:
 db $00, $00, $00, $00, $00, $00, $00
 ;--------------------------------------------------------------------------------
-; 0x180246 - 0x18024F (unused)
+org $308247 ; PC 0x180247
+; For any starting areas in single entrance caves you can specify the overworld door here
+; to enable drawing the doorframes These values should be the overworld door index+1.
+; A value of zero uses the vanilla door frame table.
+StartingAreaOverworldDoor:
+db $00, $00, $00, $00, $00, $00, $00
+;--------------------------------------------------------------------------------
+; 0x18024E - 0x18024F (unused)
 ;-------------------------------------------------------------------------------
 ; $308250 (0x180250) - $30829F (0x18029F)
 org $308250 ; PC 0x180250