The approach taken by Canonical was viewed with concern by the FSF as the company had chosen to avoid using GRUB2 thus leaving the user vulnerable as the protections available under the GPLv licence were not available to the user.
"Our main concern with the Ubuntu plan is that because they are afraid of falling out of compliance with GPLv3, they plan to drop GRUB 2 on Secure Boot systems, in favor (sic) of another bootloader with a different license that lacks GPLv3's protections for user freedom," Sullivan said.
"Their stated concern is that someone might ship an Ubuntu Certified machine with Restricted Boot (where the user cannot disable it). In order to comply with GPLv3, Ubuntu thinks it would then have to divulge its private key so that users could sign and install modified software on the restricted system."
Sullivan said this was unfounded and based on a misunderstanding of GPLv3. "We have not been able to come up with any scenario where Ubuntu would be forced to divulge a private signing key because a third-party computer manufacturer or distributor shipped Ubuntu on a Restricted Boot machine.
"In such situations, the computer distributor - not Canonical or Ubuntu - would be the one responsible for providing the information necessary for users to run modified versions of the software," he said.
The FSF said it would continue its political campaign to make users aware of the problems associated with secure boot and also make available as much documentation as possible to enable users to understand how to run their own software on their own machines.