diff --git a/virtualbox.md b/virtualbox.md
index f61ca09..c44c0f5 100644
--- a/virtualbox.md
+++ b/virtualbox.md
@@ -49,4 +49,7 @@ but windows fails with bluescreen because of [unknown], maybe the drive driver?
 
 ### virtual bridge inside
 as soon as you have a bridge inside the VM all the networking traffic is broken.
-Maybe it is the copy of the MAC, which breaks it. However, after doing things, it is working now.
\ No newline at end of file
+Maybe it is the copy of the MAC, which breaks it. However, after doing things, it is working now.
+
+## UEFI and extension pack
+the extention pack provides PXE-intel.rom. This option ROM needs DDIM support which is not possible by booting with UEFI. It is not sufficant to disable PXE boot, you need to rename/delete the rom-file itself. 
\ No newline at end of file