-When using an alternate qemu with libguestfs, usually you would need
-to write a qemu wrapper script (see section I<QEMU WRAPPERS> in
-L<guestfs(3)>). libguestfs-test-tool writes a temporary qemu wrapper
-script when you use either of the I<--qemudir> or I<--qemu> options.
+Note when using these options, you can ignore the business of qemu
+wrapper scripts (L<guestfs(3)/QEMU WRAPPERS>), since
+libguestfs-test-tool writes a wrapper script for you if one is needed.
+
+=head1 TRYING OUT A DIFFERENT KERNEL
+
+If you are using febootstrap E<ge> 3.8 then you can select which
+kernel libguestfs tries. You do this by setting the environment
+variables C<FEBOOTSTRAP_KERNEL> and/or C<FEBOOTSTRAP_MODULES>.
+
+Refer to L<febootstrap-supermin-helper(8)/ENVIRONMENT VARIABLES>
+for further information.
+
+=head1 SELF-DIAGNOSIS
+
+Refer to L<guestfs(3)/APPLIANCE BOOT PROCESS> to understand the
+messages produced by libguestfs-test-tool and/or possible errors.