Revert to hubtools 0.4.6, don't build with a default epoch value.

Don't require updating to hubtools 0.4.7. There doesn't need to be
an 'EPOC' in the caboose as it is always "0" at this step in
the release engineering flow.

Fix complementary swapped args and corresponding swapped comparison to
read correctly.

Remove vestigial epoch header check. With the decision to not use
ImageHeader.epoch, a TBD prep_image_update variant will contain
the epoch information.

drv/lpc55-update-server/src/images.rs

@@ -599,7 +599,7 @@ impl From<&[u8]> for Epoch {
 
 impl Epoch {
     pub fn can_update_to(&self, next: Epoch) -> bool {
-        self.value >= next.value
+        self.value <= next.value
     }
 }
 
@@ -611,8 +611,8 @@ impl Epoch {
 /// so that images can be rejected early, i.e. before any flash has
 /// been altered.
 pub fn check_rollback_policy(
-    next_image: ImageAccess<'_>,
     active_image: ImageAccess<'_>,
+    next_image: ImageAccess<'_>,
     complete: bool,
 ) -> Result<(), UpdateError> {
     let next_epoch = get_image_epoch(&next_image)?;

drv/lpc55-update-server/src/main.rs

@@ -202,14 +202,6 @@ impl idl::InOrderUpdateImpl for ServerImpl<'_> {
                 self.header_block = None;
                 return Err(e.into());
             }
-            let active_image =
-                ImageAccess::new_flash(&self.flash, component, slot.other());
-            if let Err(e) =
-                check_rollback_policy(active_image, next_image, false)
-            {
-                self.header_block = None;
-                return Err(e.into());
-            }
         } else {
             // Block order is enforced above. If we're here then we have
             // seen block zero already.