Update information about boot override via Redfish

Add information about legacy/EFI selector change.

Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
Change-Id: I58916e3e45f766b4a5bf4fd73490fc5b505189f5
diff --git a/REDFISH-cheatsheet.md b/REDFISH-cheatsheet.md
index 51364b0..5278fc8 100644
--- a/REDFISH-cheatsheet.md
+++ b/REDFISH-cheatsheet.md
@@ -100,5 +100,9 @@
   ```
   $ curl -k -H "X-Auth-Token: $token" -X PATCH https://${bmc}/redfish/v1/Systems/system -d '{"Boot":{"BootSourceOverrideEnabled": "Disabled","BootSourceOverrideTarget": "None"}}'
   ```
+- Change Legacy/EFI selector (valid only if host is based on the x86 CPU)
+  ```
+  $ curl -k -H "X-Auth-Token: $token" -X PATCH https://${bmc}/redfish/v1/Systems/system -d '{"Boot":{"BootSourceOverrideEnabled": "Once","BootSourceOverrideTarget": "None","BootSourceOverrideMode": "UEFI"}}'
+  ```
 
 [1]: https://www.dmtf.org/standards/redfish