diff --git a/kernel/trunk/const.inc b/kernel/trunk/const.inc
index 371a087a4e..5f9f66769a 100644
--- a/kernel/trunk/const.inc
+++ b/kernel/trunk/const.inc
@@ -313,6 +313,8 @@ BgrDataHeight       equ (OS_BASE+0x033BFFC)
 
 sys_pgmap           equ (OS_BASE+0x033C000)
 
+UPPER_KERNEL_PAGES  equ (OS_BASE+0x0400000)
+
 virtual at              (OS_BASE+0x05FFF80)
   tss  TSS
 end virtual
diff --git a/kernel/trunk/init.inc b/kernel/trunk/init.inc
index c181b5b24e..a2b965bd66 100644
--- a/kernel/trunk/init.inc
+++ b/kernel/trunk/init.inc
@@ -227,10 +227,8 @@ proc init_page_map
            jnz .scanmap
 
 ; mark kernel memory as allocated (unavailable)
-           mov ecx, [tmp_page_tabs]
+           mov ecx, (UPPER_KERNEL_PAGES-OS_BASE)/4096
            mov edx, [pg_data.pages_count-OS_BASE]
-           shr ecx, 12
-           add ecx, [pg_data.kernel_tables-OS_BASE]
            sub edx, ecx
            mov [pg_data.pages_free-OS_BASE], edx