Alright--if I go into 'ubuntu advanced options' in grub I can log into recovery mode on the current kernel (I think it's a kernel?) and can log into the non-recovery version of the previous kernel.
Tempted to just change grub so that I don't use the new kernel. Not really sure how tho.
@opie Ah--thanks! That is simple.
I'd gotten as far as GRUB_DEFAULT=1 figuring at least it'd do the advanced menu. Didn't realize the syntax for selecting the next level of options.
yeah, ya gotta count, but if you just want the kernel before the current kernel, it's always "1>3"
@rpardee
gotta update grub to change default kernel to boot
Boot previous kernel version β Ubuntu 16.04 - Technical Admin Blog
http://techadminblog.com/boot-previous-kernel-version-ubuntu-16-04/