Hello,
Were is your

> Hi,
> I'm trying to boot a Raspberry PI B+ on devuan_ascii_2.0.0_armhf_raspi2.img
>
> I'm getting a boot loop with this output: https://pastebin.com/ALTzdJxW
> Any thoughts?
>
> Should I be using the raspi1 image instead?

What is your RaspberryPi version?

In the logs I see:
"
[    2.014566] Waiting for root device /dev/mmcblk0p2...
"

Does you waited enough time?
I don' know that image,
But some do a resize of /dev/mmcblk0p2( and that could take some time.. )

--
s@po <tuxd3v@???>