Update doc

Author: weizhouapache

source/adminguide/virtual_machines.rst

@@ -1014,8 +1014,11 @@ Virtual Trusted Platform Module (vTPM) is the software-based representation of p
 CloudStack supports vTPM for instances running on KVM and VMware since 4.20.1.0 .
 
 |vm-settings-uefi-secure.png|
-On Vmware, the boot type must be set to UEFI. Boot mode can be SECURE (recommended) or LEGACY.
-On KVM, it is recommended to set boot type to UEFI, and boot mode to SECURE. UEFI is required for some Windows versions.
+UEFI setting
+
+- On Vmware, the boot type must be set to UEFI. Boot mode can be SECURE (recommended) or LEGACY.
+- On KVM, it is recommended to set boot type to UEFI, and boot mode to SECURE.
+- UEFI is required for some Windows versions.
 
 |vm-settings-virtual-tpm-model-kvm.png|
 TPM model for KVM. There are two options:
@@ -1027,7 +1030,7 @@ TPM model for KVM. There are two options:
 TPM version for KVM. There are two options:
 
 - 2.0. This is the default TPM version. It is used when version is not specified or invalid.
-- 1.2.
+- 1.2. This is not supported with CRB model.
 
 |vm-settings-virtual-tpm-enabled-vmware.png|
 Enable or disable vTPM for VMware.