blkerby · jeboo · Mar 30, 2026
diff --git a/patches/ips/fix_kraid_door.ips b/patches/ips/fix_kraid_door.ips
diff --git a/patches/rom_map/Bank A7.txt b/patches/rom_map/Bank A7.txt
@@ -1,4 +1,5 @@
 0000 - FF82: used by vanilla game
 FF82 - FFC0: escape.asm (for dachora)
-FFC0 - FFDF: map_area (for kraid)
+FFC0 - FFD0: fix_kraid_door.asm
+FFD0 - FFE0: [FREE]
 FFE0 - FFFF: flashing_placebo (for phantoon)
diff --git a/patches/rom_map/vanilla_hooks.txt b/patches/rom_map/vanilla_hooks.txt
@@ -1096,6 +1096,7 @@ $a6b2ba - gray_doors.asm
 $a6b297 - gray_doors.asm
 
 [BANK A7]
+$a7b0fb - fix_kraid_door.asm
 $a7c81e - escape.asm
 $a7f892 - escape.asm
 $a7dd7f - flashing_placebo.asm

diff --git a/patches/src/fix_kraid_door.asm b/patches/src/fix_kraid_door.asm
@@ -0,0 +1,27 @@
+; Fix bug when entering Kraid from right door and leaving just as he
+; finishes ascending. The boss AI checks that Samus is left of Kraid,
+; and will adjust her X coordinate if needed. This can lead to a bugged
+; Samus position or OOB error if it occurs during the door transition.
+;
+; Reported by P.JBoy, fix by Stag Shot
+
+lorom
+
+!bank_a7_free_space_start = $a7ffc0
+!bank_a7_free_space_end = $a7ffd0
+
+org $a7b0fb
+    jmp  fix_kraid_door
+
+org !bank_a7_free_space_start
+fix_kraid_door:
+    lda $795        ; door transition flag
+    beq .resume
+    rts             ; skip rest of func
+
+.resume
+    lda $af6        ; replaced code
+    clc             ;
+    jmp $b0ff       ; resume func
+
+assert pc() < !bank_a7_free_space_end
diff --git a/rust/maprando/src/patch.rs b/rust/maprando/src/patch.rs
@@ -492,6 +492,7 @@ impl Patcher<'_> {
                 "fast_big_boy_cutscene",
                 "fix_kraid_vomit",
                 "fix_kraid_hud",
+                "fix_kraid_door",
                 "escape_autosave",
                 "boss_exit",
                 "load_plms_early",