:: commit 23a63ef476e6febc26c45dd25c5e42d0c067369e

diff --git a/common/protos/linux.c b/common/protos/linux.c
index 5671a395..0fb37232 100644
--- a/common/protos/linux.c
+++ b/common/protos/linux.c
@@ -30,6 +30,8 @@ noreturn void linux_spinup(void *entry, void *boot_params);
 #define E820_MAX_ENTRIES_ZEROPAGE 128
 #define EDDMAXNR 6
 
+#define XLF_KERNEL_64 (1 << 0)
+
 struct setup_header {
     uint8_t    setup_sects;
     uint16_t    root_flags;
@@ -591,13 +593,18 @@ set_textmode:;
     boot_params->efi_info.efi_memmap    = (uint32_t)(uint64_t)(uintptr_t)efi_mmap;
     boot_params->efi_info.efi_memmap_hi = (uint32_t)((uint64_t)(uintptr_t)efi_mmap >> 32);
 #if defined (__x86_64__)
-    boot_params->efi_info.efi_memmap_size     = efi_mmap_size;
+    if ((setup_header->xloadflags & XLF_KERNEL_64) == 0) {
 #elif defined (__i386__)
-    // A memmap size of 0 will cause Linux to force bail out of trying to use
-    // 32-bit EFI runtime services without ignoring other EFI info.
-    // XXX: Figure out why 64-bit Linux hangs if trying to use 32-bit boot services.
-    boot_params->efi_info.efi_memmap_size     = 0;
+    if ((setup_header->xloadflags & XLF_KERNEL_64) != 0) {
 #endif
+        // A memmap size of 0 will cause Linux to force bail out of trying to use
+        // mismatched bitness EFI runtime services without ignoring other EFI info.
+        // XXX: Figure out why 64-bit Linux hangs if trying to use 32-bit boot services,
+        //      and vice versa.
+        boot_params->efi_info.efi_memmap_size = 0;
+    } else {
+        boot_params->efi_info.efi_memmap_size = efi_mmap_size;
+    }
     boot_params->efi_info.efi_memdesc_size    = efi_desc_size;
     boot_params->efi_info.efi_memdesc_version = efi_desc_ver;
 #endif