website: mark old arm disk images as old

Also briefly document key parameters of the latest image
ubuntu-18.04-arm64-docker.img.bz2.

Change-Id: I0949fd9364aae6be359d260faee348d0a1d36f4f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-website/+/38035
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: Bobby R. Bruce <bbruce@ucdavis.edu>
diff --git a/_pages/documentation/general_docs/fullsystem/guest_binaries.md b/_pages/documentation/general_docs/fullsystem/guest_binaries.md
index 8e35f0e..1cbd6a3 100644
--- a/_pages/documentation/general_docs/fullsystem/guest_binaries.md
+++ b/_pages/documentation/general_docs/fullsystem/guest_binaries.md
@@ -30,15 +30,25 @@
 ##### Latest Linux Disk Images (**recommended**)
 
 * <http://dist.gem5.org/dist/current/arm/disks/ubuntu-18.04-arm64-docker.img.bz2>
-* <http://dist.gem5.org/dist/current/arm/disks/aarch64-ubuntu-trusty-headless.img.bz2>
+
+  Partition table: yes
+
+  gem5 init: `/init.gem5`
+
 * <http://dist.gem5.org/dist/current/arm/disks/aarch32-ubuntu-natty-headless.img.bz2>
-* <http://dist.gem5.org/dist/current/arm/disks/linaro-minimal-aarch64.img.bz2>
-* <http://dist.gem5.org/dist/current/arm/disks/linux-aarch32-ael.img.bz2>
 
 ##### Old Linux Kernel/Disk Image
 
 These images are not supported. If you run into problems, we will do our best to help, but there is no guarantee these will work with the latest gem5 version
 
+###### Disk images only
+
+* <http://dist.gem5.org/dist/current/arm/disks/aarch64-ubuntu-trusty-headless.img.bz2>
+* <http://dist.gem5.org/dist/current/arm/disks/linaro-minimal-aarch64.img.bz2>
+* <http://dist.gem5.org/dist/current/arm/disks/linux-aarch32-ael.img.bz2>
+
+###### Disk and kernel images
+
 * <http://dist.gem5.org/dist/current/arm/aarch-system-20170616.tar.xz>
 * <http://dist.gem5.org/dist/current/arm/aarch-system-20180409.tar.xz>
 * <http://dist.gem5.org/dist/current/arm/arm-system-dacapo-2011-08.tgz>