diff --git a/src/libostree/ostree-sysroot-deploy.c b/src/libostree/ostree-sysroot-deploy.c
index ebc0b4fcb2..64a4fb26e2 100644
--- a/src/libostree/ostree-sysroot-deploy.c
+++ b/src/libostree/ostree-sysroot-deploy.c
@@ -2657,6 +2657,7 @@ auto_early_prune_old_deployments (OstreeSysroot *self, GPtrArray *new_deployment
       /* it wasn't in current_bootcsums; add */
       net_new_bootcsum_dirs_total_size += bootdir_size;
     }
+  g_autofree char *net_new_formatted = g_format_size (net_new_bootcsum_dirs_total_size);
 
   {
     gboolean bootfs_has_space = FALSE;
@@ -2667,9 +2668,13 @@ auto_early_prune_old_deployments (OstreeSysroot *self, GPtrArray *new_deployment
     /* does the bootfs have enough free space for temporarily holding both the new
      * and old bootdirs? */
     if (bootfs_has_space)
-      return TRUE; /* nothing to do! */
+      {
+        g_printerr ("bootfs is sufficient for calculated new size: %s\n", net_new_formatted);
+        return TRUE; /* nothing to do! */
+      }
   }
 
+  g_printerr ("bootfs requires additional space: %s\n", net_new_formatted);
   /* OK, we would fail if we tried to write the new bootdirs. Is it salvageable?
    * First, calculate how much space we could save with the bootcsums scheduled
    * for removal. */
@@ -2680,14 +2685,17 @@ auto_early_prune_old_deployments (OstreeSysroot *self, GPtrArray *new_deployment
         bootcsum_dirs_to_remove_total_size += GPOINTER_TO_UINT (sizep);
     }
 
+  {
+    g_autofree char *to_remove_formated = g_format_size (bootcsum_dirs_to_remove_total_size);
+    g_printerr ("Size to prune from bootfs: %s\n", to_remove_formated);
+  }
+
   if (net_new_bootcsum_dirs_total_size > bootcsum_dirs_to_remove_total_size)
     {
       /* Check whether if we did early prune, we'd have enough space to write
        * the new bootcsum dirs. */
       gboolean bootfs_has_space = FALSE;
-      if (!dfd_fallocate_check (
-              self->boot_fd, net_new_bootcsum_dirs_total_size - bootcsum_dirs_to_remove_total_size,
-              &bootfs_has_space, error))
+      if (!dfd_fallocate_check (self->boot_fd, required_new_space, &bootfs_has_space, error))
         return glnx_prefix_error (error, "Checking if prune would give bootfs sufficient space");
 
       if (!bootfs_has_space)