Plymouth not displaying splash

Plymouth version 0.9.2-3+rpi1
Raspbian 4.4.30-v7+

Following the guide at https://github.com/notro/fbtft/wiki/Bootsplash for a SSD1322 based framebuffer display, Plymouth displays "Loading, please wait". Some themes do not progress to the login prompt but others do. No graphic is ever displayed. The same behaviour is noted when using the "text" theme.

Expected behaviour is to display a graphic based on the loaded theme before reaching the login prompt.

/boot/cmdline.txt contains "fbcon=map:10 splash quiet plymouth.ignore-serial-consoles".

/etc/initramfs-tools/conf.d/fb1 contains "export FRAMEBUFFER=/dev/fb1".

/etc/initramfs-tools/modules has the correct drivers and these are loaded and tested as working.

There are a number of others with this same or similar problem on a range of forums including...

https://www.raspberrypi.org/forums/viewtopic.php?t=97032&p=674028