I successfully installed MultiROM on my Nexus 7 (2013), and I can boot CyanogenMod.
Therefore, I followed the excellent article "Multi-Booting the Nexus 7 Tablet" that was published in the Linux Journal:
Unfortunately, booting Ubuntu Touch does not work. The error message is:
"Error. Kexec-hardboot support required to boot this ROM. Use kernel with kexec-hardboot support."
However, for the installation I chose a patched kernel that includes the kexec-hardboot patch as described here:
The link contains the following advice:
"Now that your bootloader is unlocked, you can proceed to the trickiest part of this process—installing MultiROM. Grab a copy of it from the XDA-Developers MultiROM thread (the link is in the Resources section of this article; currently the filename is multirom_v10_n7-signed.zip). You'll also need to get the modified TWRP install file (TWRP_multirom_n7_20130404.img) and a patched kernel (kernel_kexec_422.zip). Rename the TWRP install file to recovery.img, then hook your tablet back up to your computer, and place these files in the root of its filesystem (keep the .zip files zipped—don't unzip them). "
This is what I did, I used:
Any ideas how to get Ubuntu Touch running?