Cannot Emerge Debian-sources

When following the funtoo wiki’s install guide, it has you emerge debian-sources as an easy solution to getting a kernel.

This emerge fails and looks something like this:

>>> Installing (1 of 1) sys-kernel/debian-sources-3.2.41
*
* To avoid automounting and auto(un)installing with /boot,
* just export the DONT_MOUNT_BOOT variable.
*
mount: /dev/sda1 is already mounted or /boot busy
*
* Cannot automatically mount your /boot partition.
* Your boot partition has to be mounted rw before the installation
* can continue. debian-sources needs to install important files there.
*
* ERROR: sys-kernel/debian-sources-3.2.41 failed (preinst phase):
*   Please mount your /boot partition manually!
*
* Call stack:
*     ebuild.sh, line   93:  Called pkg_preinst
*   environment, line 2087:  Called mount-boot_pkg_preinst
*   environment, line 1896:  Called mount-boot_mount_boot_partition
*   environment, line 1885:  Called die
* The specific snippet of code:
*               die "Please mount your /boot partition manually!";
*
* If you need support, post the output of `emerge --info '=sys-kernel/debian-sources-3.2.41'`,
* the complete build log and the output of `emerge -pqv '=sys-kernel/debian-sources-3.2.41'`.
* The complete build log is located at '/var/tmp/portage/sys-kernel/debian-sources-3.2.41/temp/build.log'.
* The ebuild environment file is located at '/var/tmp/portage/sys-kernel/debian-sources-3.2.41/temp/environment'.
* Working directory: '/usr/lib/portage/pym'
* S: '/var/tmp/portage/sys-kernel/debian-sources-3.2.41/work/linux-3.2.41'
!!! FAILED preinst: 1

>>> Failed to install sys-kernel/debian-sources-3.2.41, Log file:
>>>  '/var/tmp/portage/sys-kernel/debian-sources-3.2.41/temp/build.log'

* Messages for package sys-kernel/debian-sources-3.2.41:

*
* To avoid automounting and auto(un)installing with /boot,
* just export the DONT_MOUNT_BOOT variable.
*
*
* Cannot automatically mount your /boot partition.
* Your boot partition has to be mounted rw before the installation
* can continue. debian-sources needs to install important files there.
*
* ERROR: sys-kernel/debian-sources-3.2.41 failed (preinst phase):
*   Please mount your /boot partition manually!
*
* Call stack:
*     ebuild.sh, line   93:  Called pkg_preinst
*   environment, line 2087:  Called mount-boot_pkg_preinst
*   environment, line 1896:  Called mount-boot_mount_boot_partition
*   environment, line 1885:  Called die
* The specific snippet of code:
*               die "Please mount your /boot partition manually!";
*
* If you need support, post the output of `emerge --info '=sys-kernel/debian-sources-3.2.41'`,
* the complete build log and the output of `emerge -pqv '=sys-kernel/debian-sources-3.2.41'`.
* The complete build log is located at '/var/tmp/portage/sys-kernel/debian-sources-3.2.41/temp/build.log'.
* The ebuild environment file is located at '/var/tmp/portage/sys-kernel/debian-sources-3.2.41/temp/environment'.
* Working directory: '/usr/lib/portage/pym'
* S: '/var/tmp/portage/sys-kernel/debian-sources-3.2.41/work/linux-3.2.41'

To fix this and proceed with the install process we need to:

cat /proc/mounts > /etc/mtab

Now we can re-emerge the debian-sources and it should install and compile correctly.