Update instructions on the crypto compatibility test
The instructions in the comment were out of date. Even though it's not
expected that they'll change, it's better that the comments are correct.
. ./common.sh
-# To create the files for this test, run 024_metadata_sig.test,
-# run:
+# To create the files for this test, edit 024_metadata_sig.test so
+# that it exits with an error code. This will keep its work directory
+# around. Then run it.
#
-# $ base64 fwup-key.pub
-# $ base64 work/fwup.fw
+# After that, base64 encode the public key and signed .fw file:
+#
+# $ base64 work-024_metadata_sig.test/fwup-key.pub
+# $ base64 work-024_metadata_sig.test/fwup.fw
#
# Save the results here.
