fix(xo-server/vm.set): fix converting to BIOS (#5895)

Fixes xoa-support#3991

CHANGELOG.unreleased.md

@@ -12,6 +12,7 @@
 > Users must be able to say: “I had this issue, happy to know it's fixed”
 
 - [SSH keys] Allow SSH key to be broken anywhere to avoid breaking page formatting (Thanks @tstivers1990!) [#5891](https://github.com/vatesfr/xen-orchestra/issues/5891) (PR [#5892](https://github.com/vatesfr/xen-orchestra/pull/5892))
+- [VM/Advanced] Fix conversion from UEFI to BIOS boot firmware (PR [#5895](https://github.com/vatesfr/xen-orchestra/pull/5895))
 
 ### Packages to release
 
@@ -30,4 +31,5 @@
 >
 > In case of conflict, the highest (lowest in previous list) `$version` wins.
 
+- xo-server patch
 - xo-web patch

packages/xo-server/src/xapi/mixins/vm.mjs

@@ -451,7 +451,11 @@ export default {
       set: (secureBoot, vm) => vm.update_platform('secureboot', secureBoot.toString()),
     },
     hvmBootFirmware: {
-      set: (firmware, vm) => vm.update_HVM_boot_params('firmware', firmware),
+      set: (firmware, vm) =>
+        Promise.all([
+          vm.update_HVM_boot_params('firmware', firmware),
+          vm.update_platform('device-model', 'qemu-upstream-' + (firmware === 'uefi' ? 'uefi' : 'compat')),
+        ]),
     },
   }),