importer.architecture has the following code 
```ruby
# On solaris architecture fact is harwareisa
name = case os_name
          when /(sunos|solaris)/i
            facts[:hardwareisa]
          else
            facts[:architecture] || facts[:hardwareisa]
          end
 # ensure that we convert debian legacy to standard
 name = "x86_64" if name == "amd64"
 Architecture.find_or_create_by_name name unless name.blank?
```
since facter is running in a tiny-core context, os is known, fact architecture is not relevant and hardwareisa is unknown.
This code is not useful in this case.