diff --git a/tools/efs_parser.py b/tools/efs_parser.py
index a16830a..cbcb0aa 100644
--- a/tools/efs_parser.py
+++ b/tools/efs_parser.py
@@ -3,10 +3,15 @@
 from struct import unpack
 import zlib
 
+EFS_MAGIC = b"\xAA\x55\xAA\x55"
+PSP_COOKIE = b"$PSP"
+PSPL2_COOKIE = b"$PL2"
+PSP2_COOKIE = b"2PSP"
+BHD_COOKIE = b"$BHD"
+BHDL2_COOKIE = b"$BL2"
+BHD2_COOKIE = b"2BHD"
 
 def extract_efs(rom):
-    efs_magic = b"\xAA\x55\xAA\x55"
-    
     efs_offsets = [
         0x020000,
         0x820000,
@@ -17,22 +22,21 @@ def extract_efs(rom):
     ]
 
     for offset in efs_offsets:
-        if rom[offset:offset+4] == efs_magic:
+        if rom[offset:offset+4] == EFS_MAGIC:
             return rom[offset:offset+0x4B]
 
 def parse_efs(efs):
     print("Parsing EFS")
-    efs_magic = b"\xAA\x55\xAA\x55"
 
-    if efs[0x0:0x4] != efs_magic:
+    if efs[0x0:0x4] != EFS_MAGIC:
         print(f"Invalid EFS magic {efs[0:4]}")
         exit()
 
 
     dir_offsets = []
-    for offset in range(0x14, 0x30, 4):
+    for offset in range(0x10, 0x30, 4):
         ptr = int.from_bytes(efs[offset:offset+4], "little")
-        if ptr != 0x00000000 and ptr != 0xFFFFFFFE:
+        if ptr != 0x00000000 and ptr != 0xFFFFFFFE and ptr != 0xFFFFFFFF:
             dir_offsets.append(ptr)
 
     print(f"# EFS entries: {len(dir_offsets)}")
@@ -45,13 +49,13 @@ def parse_efs(efs):
 def parse_dir(rom, offset):
     magic = rom[offset:offset+4]
 
-    if magic == b"$PSP":
+    if magic == PSP_COOKIE:
         parse_psp_dir(rom, offset)
         pass
-    elif magic == b"2PSP" or magic == b"2BHD":
+    elif magic == PSP2_COOKIE or magic == BHD2_COOKIE:
         parse_psp_combodir(rom, offset)
         pass
-    elif magic == b"$BHD":
+    elif magic == BHD_COOKIE:
         parse_bios_dir(rom, offset)
         pass
     else:
@@ -66,7 +70,7 @@ def parse_psp_dir(rom, offset):
     psp_hdr = rom[offset:offset+0x10]
 
     psp_magic = psp_hdr[0:4]
-    if psp_magic != b"$PSP" and psp_magic != b"$PL2":
+    if psp_magic != PSP_COOKIE and psp_magic != PSPL2_COOKIE:
         print(f"Invalid magic {psp_magic} when parsing PSP directory")
         exit()
 
@@ -149,7 +153,7 @@ def parse_psp_combodir(rom, offset):
     psp_hdr = rom[offset:offset+0x20]
 
     psp_magic = psp_hdr[0:4]
-    if psp_magic != b"2PSP" and psp_magic != b"2BHD":
+    if psp_magic != PSP2_COOKIE and psp_magic != BHD2_COOKIE:
         print(f"Invalid magic {psp_magic} when parsing PSP directory")
         exit()
 
@@ -214,7 +218,7 @@ def parse_bios_dir(rom, offset):
     bios_hdr = rom[offset:offset+0x10]
 
     bios_magic = bios_hdr[0x0:0x4]
-    if bios_magic != b"$BHD" and bios_magic != b"$BL2":
+    if bios_magic != BHD_COOKIE and bios_magic != BHDL2_COOKIE:
         print(f"Invalid magic {bios_magic} when parsing BIOS directory")
         exit()