diff --git a/src/game/game_128f30.c b/src/game/game_128f30.c
index ba08743c4..4157d47a4 100644
--- a/src/game/game_128f30.c
+++ b/src/game/game_128f30.c
@@ -95,94 +95,27 @@ glabel func0f128f30
 /*  f129068:	27bd0058 */ 	addiu	$sp,$sp,0x58
 );
 
-GLOBAL_ASM(
-glabel func0f12906c
-/*  f12906c:	27bdffa8 */ 	addiu	$sp,$sp,-88
-/*  f129070:	3c0e8f80 */ 	lui	$t6,0x8f80
-/*  f129074:	3c0f3108 */ 	lui	$t7,0x3108
-/*  f129078:	afb50028 */ 	sw	$s5,0x28($sp)
-/*  f12907c:	afb40024 */ 	sw	$s4,0x24($sp)
-/*  f129080:	afb30020 */ 	sw	$s3,0x20($sp)
-/*  f129084:	afb10018 */ 	sw	$s1,0x18($sp)
-/*  f129088:	afb00014 */ 	sw	$s0,0x14($sp)
-/*  f12908c:	35efb3c1 */ 	ori	$t7,$t7,0xb3c1
-/*  f129090:	35ce9f47 */ 	ori	$t6,$t6,0x9f47
-/*  f129094:	0085082b */ 	sltu	$at,$a0,$a1
-/*  f129098:	00a0a825 */ 	or	$s5,$a1,$zero
-/*  f12909c:	afbf002c */ 	sw	$ra,0x2c($sp)
-/*  f1290a0:	afb2001c */ 	sw	$s2,0x1c($sp)
-/*  f1290a4:	afa60060 */ 	sw	$a2,0x60($sp)
-/*  f1290a8:	00803825 */ 	or	$a3,$a0,$zero
-/*  f1290ac:	00008825 */ 	or	$s1,$zero,$zero
-/*  f1290b0:	afae0048 */ 	sw	$t6,0x48($sp)
-/*  f1290b4:	afaf004c */ 	sw	$t7,0x4c($sp)
-/*  f1290b8:	00009825 */ 	or	$s3,$zero,$zero
-/*  f1290bc:	0000a025 */ 	or	$s4,$zero,$zero
-/*  f1290c0:	10200016 */ 	beqz	$at,.L0f12911c
-/*  f1290c4:	00808025 */ 	or	$s0,$a0,$zero
-/*  f1290c8:	afa40058 */ 	sw	$a0,0x58($sp)
-/*  f1290cc:	27b20048 */ 	addiu	$s2,$sp,0x48
-.L0f1290d0:
-/*  f1290d0:	92180000 */ 	lbu	$t8,0x0($s0)
-/*  f1290d4:	8fad004c */ 	lw	$t5,0x4c($sp)
-/*  f1290d8:	3239000f */ 	andi	$t9,$s1,0xf
-/*  f1290dc:	03384004 */ 	sllv	$t0,$t8,$t9
-/*  f1290e0:	8fac0048 */ 	lw	$t4,0x48($sp)
-/*  f1290e4:	010d7821 */ 	addu	$t7,$t0,$t5
-/*  f1290e8:	000857c3 */ 	sra	$t2,$t0,0x1f
-/*  f1290ec:	01ed082b */ 	sltu	$at,$t7,$t5
-/*  f1290f0:	002a7021 */ 	addu	$t6,$at,$t2
-/*  f1290f4:	01cc7021 */ 	addu	$t6,$t6,$t4
-/*  f1290f8:	afae0048 */ 	sw	$t6,0x48($sp)
-/*  f1290fc:	afaf004c */ 	sw	$t7,0x4c($sp)
-/*  f129100:	0c004b87 */ 	jal	func00012e1c
-/*  f129104:	02402025 */ 	or	$a0,$s2,$zero
-/*  f129108:	26100001 */ 	addiu	$s0,$s0,0x1
-/*  f12910c:	26310007 */ 	addiu	$s1,$s1,0x7
-/*  f129110:	1615ffef */ 	bne	$s0,$s5,.L0f1290d0
-/*  f129114:	02629826 */ 	xor	$s3,$s3,$v0
-/*  f129118:	8fa70058 */ 	lw	$a3,0x58($sp)
-.L0f12911c:
-/*  f12911c:	26b0ffff */ 	addiu	$s0,$s5,-1
-/*  f129120:	0207082b */ 	sltu	$at,$s0,$a3
-/*  f129124:	14200014 */ 	bnez	$at,.L0f129178
-/*  f129128:	27b20048 */ 	addiu	$s2,$sp,0x48
-/*  f12912c:	24f5ffff */ 	addiu	$s5,$a3,-1
-.L0f129130:
-/*  f129130:	92090000 */ 	lbu	$t1,0x0($s0)
-/*  f129134:	8fab004c */ 	lw	$t3,0x4c($sp)
-/*  f129138:	3238000f */ 	andi	$t8,$s1,0xf
-/*  f12913c:	0309c804 */ 	sllv	$t9,$t1,$t8
-/*  f129140:	8faa0048 */ 	lw	$t2,0x48($sp)
-/*  f129144:	032b6821 */ 	addu	$t5,$t9,$t3
-/*  f129148:	001947c3 */ 	sra	$t0,$t9,0x1f
-/*  f12914c:	01ab082b */ 	sltu	$at,$t5,$t3
-/*  f129150:	00286021 */ 	addu	$t4,$at,$t0
-/*  f129154:	018a6021 */ 	addu	$t4,$t4,$t2
-/*  f129158:	afac0048 */ 	sw	$t4,0x48($sp)
-/*  f12915c:	afad004c */ 	sw	$t5,0x4c($sp)
-/*  f129160:	0c004b87 */ 	jal	func00012e1c
-/*  f129164:	02402025 */ 	or	$a0,$s2,$zero
-/*  f129168:	2610ffff */ 	addiu	$s0,$s0,-1
-/*  f12916c:	26310003 */ 	addiu	$s1,$s1,0x3
-/*  f129170:	1615ffef */ 	bne	$s0,$s5,.L0f129130
-/*  f129174:	0282a026 */ 	xor	$s4,$s4,$v0
-.L0f129178:
-/*  f129178:	8faf0060 */ 	lw	$t7,0x60($sp)
-/*  f12917c:	02607025 */ 	or	$t6,$s3,$zero
-/*  f129180:	0280c025 */ 	or	$t8,$s4,$zero
-/*  f129184:	a5ee0000 */ 	sh	$t6,0x0($t7)
-/*  f129188:	a5f80002 */ 	sh	$t8,0x2($t7)
-/*  f12918c:	8fbf002c */ 	lw	$ra,0x2c($sp)
-/*  f129190:	8fb50028 */ 	lw	$s5,0x28($sp)
-/*  f129194:	8fb40024 */ 	lw	$s4,0x24($sp)
-/*  f129198:	8fb30020 */ 	lw	$s3,0x20($sp)
-/*  f12919c:	8fb2001c */ 	lw	$s2,0x1c($sp)
-/*  f1291a0:	8fb10018 */ 	lw	$s1,0x18($sp)
-/*  f1291a4:	8fb00014 */ 	lw	$s0,0x14($sp)
-/*  f1291a8:	03e00008 */ 	jr	$ra
-/*  f1291ac:	27bd0058 */ 	addiu	$sp,$sp,0x58
-);
+void crcCalculateU16Pair(u8 *start, u8 *end, u16 *checksum)
+{
+	u8 *ptr;
+	u32 salt = 0;
+	u64 seed = 0x8f809f473108b3c1;
+	u32 sum1 = 0;
+	u32 sum2 = 0;
+
+	for (ptr = start; ptr < end; ptr++, salt += 7) {
+		seed += *ptr << (salt & 0x0f);
+		sum1 ^= func00012e1c(&seed);
+	}
+
+	for (ptr = end - 1; ptr >= start; ptr--, salt += 3) {
+		seed += *ptr << (salt & 0x0f);
+		sum2 ^= func00012e1c(&seed);
+	}
+
+	checksum[0] = sum1 & 0xffff;
+	checksum[1] = sum2 & 0xffff;
+}
 
 GLOBAL_ASM(
 glabel func0f1291b0
diff --git a/src/game/pak/pak.c b/src/game/pak/pak.c
index 3fd3babcf..4755ca082 100644
--- a/src/game/pak/pak.c
+++ b/src/game/pak/pak.c
@@ -3262,7 +3262,7 @@ const char var7f1ae6f4nb[] = "dumpeeprom";
 
 void pakCalculateChecksum(u8 *start, u8 *end, u16 *checksum)
 {
-	func0f12906c(start, end, checksum);
+	crcCalculateU16Pair(start, end, checksum);
 }
 
 #if VERSION >= VERSION_NTSC_1_0
diff --git a/src/include/game/game_128f30.h b/src/include/game/game_128f30.h
index e072560a9..0153c70d3 100644
--- a/src/include/game/game_128f30.h
+++ b/src/include/game/game_128f30.h
@@ -5,7 +5,7 @@
 #include "types.h"
 
 u32 func0f128f30(void);
-void func0f12906c(u8 *start, u8 *end, u16 *checksum);
+void crcCalculateU16Pair(u8 *start, u8 *end, u16 *checksum);
 u32 func0f1291b0(void);
 u32 func0f1291f8(void);