diff --git a/hypervisor/arch/x86/boot/cpu_primary.S b/hypervisor/arch/x86/boot/cpu_primary.S
index d0012a983..11d08155c 100644
--- a/hypervisor/arch/x86/boot/cpu_primary.S
+++ b/hypervisor/arch/x86/boot/cpu_primary.S
@@ -314,9 +314,3 @@ cpu_primary32_pdt_addr:
     .quad  address + 0x83
     address = address + 0x200000
     .endr
-
-#ifdef CONFIG_MULTIBOOT2
-    .global efiloader_sig
-efiloader_sig:
-    .asciz    "EL64"
-#endif
diff --git a/hypervisor/arch/x86/init.c b/hypervisor/arch/x86/init.c
index d6dde9b52..3d2b6259a 100644
--- a/hypervisor/arch/x86/init.c
+++ b/hypervisor/arch/x86/init.c
@@ -16,10 +16,10 @@
 #include <ld_sym.h>
 #include <multiboot.h>
 
-/* The following are assembly varaibles defined in arch/x86/boot/cpu_primary.S */
-/* boot_regs store the multiboot info magic and address */
+/* boot_regs store the multiboot info magic and address, defined in
+   arch/x86/boot/cpu_primary.S.
+   */
 extern uint32_t boot_regs[2];
-extern char *efiloader_sig;
 
 /* Push sp magic to top of stack for call trace */
 #define SWITCH_TO(rsp, to)                                              \
@@ -91,7 +91,7 @@ void init_primary_pcpu(void)
 	/* Clear BSS */
 	(void)memset(&ld_bss_start, 0U, (size_t)(&ld_bss_end - &ld_bss_start));
 
-	init_acrn_multiboot_info(boot_regs[0], boot_regs[1], efiloader_sig);
+	init_acrn_multiboot_info(boot_regs[0], boot_regs[1]);
 
 	init_debug_pre();
 
diff --git a/hypervisor/boot/include/multiboot.h b/hypervisor/boot/include/multiboot.h
index cd929717c..e59706181 100644
--- a/hypervisor/boot/include/multiboot.h
+++ b/hypervisor/boot/include/multiboot.h
@@ -79,7 +79,7 @@ struct acrn_multiboot_info {
 	struct efi_info		mi_efi_info;
 };
 
-void init_acrn_multiboot_info(uint32_t magic, uint32_t info, char *sig);
+void init_acrn_multiboot_info(uint32_t magic, uint32_t info);
 int32_t sanitize_acrn_multiboot_info(uint32_t magic, uint32_t info);
 struct acrn_multiboot_info *get_acrn_multiboot_info(void);
 
diff --git a/hypervisor/boot/multiboot/multiboot.c b/hypervisor/boot/multiboot/multiboot.c
index ce1dce357..fc2095a3f 100644
--- a/hypervisor/boot/multiboot/multiboot.c
+++ b/hypervisor/boot/multiboot/multiboot.c
@@ -67,7 +67,7 @@ static struct acrn_multiboot_info acrn_mbi = { 0U };
 
 static int32_t mbi_status;
 
-void init_acrn_multiboot_info(uint32_t magic, uint32_t info, char *sig)
+void init_acrn_multiboot_info(uint32_t magic, uint32_t info)
 {
 	if (boot_from_multiboot1(magic, info)) {
 		struct multiboot_info *mbi = (struct multiboot_info *)(hpa2hva_early((uint64_t)info));
@@ -84,7 +84,7 @@ void init_acrn_multiboot_info(uint32_t magic, uint32_t info, char *sig)
 		mbi_status = 0;
 #ifdef CONFIG_MULTIBOOT2
 	} else if (boot_from_multiboot2(magic)) {
-		mbi_status = multiboot2_to_acrn_mbi(&acrn_mbi, hpa2hva_early((uint64_t)info), sig);
+		mbi_status = multiboot2_to_acrn_mbi(&acrn_mbi, hpa2hva_early((uint64_t)info));
 #endif
 	} else {
 		mbi_status = -ENODEV;
diff --git a/hypervisor/boot/multiboot/multiboot2.c b/hypervisor/boot/multiboot/multiboot2.c
index 377995232..e3611ac90 100644
--- a/hypervisor/boot/multiboot/multiboot2.c
+++ b/hypervisor/boot/multiboot/multiboot2.c
@@ -36,11 +36,11 @@ static void mb2_mods_to_mbi(struct acrn_multiboot_info *mbi,
 /**
  * @pre mbi != NULL && mb2_tag_efi64 != 0
  */
-static void mb2_efi64_to_mbi(struct acrn_multiboot_info *mbi, const struct multiboot2_tag_efi64 *mb2_tag_efi64,
-		char *sig)
+static void mb2_efi64_to_mbi(struct acrn_multiboot_info *mbi, const struct multiboot2_tag_efi64 *mb2_tag_efi64)
 {
+	const uint32_t efiloader_sig = 0x34364c45; /* "EL64" */
 	mbi->mi_efi_info.efi_systab = (uint32_t)(uint64_t)mb2_tag_efi64->pointer;
-	mbi->mi_efi_info.efi_loader_signature = (uint32_t)(uint64_t)sig;
+	mbi->mi_efi_info.efi_loader_signature = efiloader_sig;
 	mbi->mi_flags |= MULTIBOOT_INFO_HAS_EFI64;
 }
 
@@ -61,7 +61,7 @@ static void mb2_efimmap_to_mbi(struct acrn_multiboot_info *mbi,
 /**
  * @pre mbi != NULL
  */
-int32_t multiboot2_to_acrn_mbi(struct acrn_multiboot_info *mbi, void *mb2_info, char *sig)
+int32_t multiboot2_to_acrn_mbi(struct acrn_multiboot_info *mbi, void *mb2_info)
 {
 	int32_t ret = 0;
 	struct multiboot2_tag *mb2_tag, *mb2_tag_end;
@@ -92,7 +92,7 @@ int32_t multiboot2_to_acrn_mbi(struct acrn_multiboot_info *mbi, void *mb2_info,
 			mbi->mi_acpi_rsdp_va = ((struct multiboot2_tag_new_acpi *)mb2_tag)->rsdp;
 			break;
 		case MULTIBOOT2_TAG_TYPE_EFI64:
-			mb2_efi64_to_mbi(mbi, (const struct multiboot2_tag_efi64 *)mb2_tag, sig);
+			mb2_efi64_to_mbi(mbi, (const struct multiboot2_tag_efi64 *)mb2_tag);
 			break;
 		case MULTIBOOT2_TAG_TYPE_EFI_MMAP:
 			mb2_efimmap_to_mbi(mbi, (const struct multiboot2_tag_efi_mmap *)mb2_tag);
diff --git a/hypervisor/boot/multiboot/multiboot_priv.h b/hypervisor/boot/multiboot/multiboot_priv.h
index bb19a58a8..926493384 100644
--- a/hypervisor/boot/multiboot/multiboot_priv.h
+++ b/hypervisor/boot/multiboot/multiboot_priv.h
@@ -89,7 +89,7 @@ static inline bool boot_from_multiboot2(uint32_t magic)
 	return (magic == MULTIBOOT2_INFO_MAGIC);
 }
 
-int32_t multiboot2_to_acrn_mbi(struct acrn_multiboot_info *mbi, void *mb2_info, char *sig);
+int32_t multiboot2_to_acrn_mbi(struct acrn_multiboot_info *mbi, void *mb2_info);
 #endif
 
 static inline bool boot_from_multiboot1(uint32_t magic, uint32_t info)