diff --git a/debian/changelog b/debian/changelog
index 5701f75f..fadf93f2 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -4,7 +4,17 @@ livecd-rootfs (25.10.24) UNRELEASED; urgency=medium
   * Limit permissions for /etc/netplan/01-network-manager.yaml to
     root read-write. (LP: #2119020)
 
- -- Chad Smith <chad.smith@canonical.com>  Thu, 18 Sep 2025 22:33:28 -0600
+  [ Chloé 'kajiya' Smith ]
+  * Increase CPC disk-image base imagesize to 2.5GB
+    * In the ubuntu-cpc disk-image binary we need to avail of the ever increasing size
+      of packages. 2.2GB is now just a bit too small leading to `No space
+      left on device` errors when the binary hits `grub-install`. This change
+      increases $imagesize to 2.5GB (in the binary as an override, initially
+      implemented in ecaaf0484 by dlalaj). Also now run `df` just after the
+      grub-pc && grub2-common installs to make for easier debugging in the future.
+      (LP: #2115811)
+
+ -- Chloé 'kajiya' Smith <chloe.smith@canonical.com>  Fri, 19 Sep 2025 13:07:00 +0100
 
 livecd-rootfs (25.10.23) questing; urgency=medium
 
diff --git a/live-build/functions b/live-build/functions
index 2926e858..a4b27bd0 100644
--- a/live-build/functions
+++ b/live-build/functions
@@ -1,6 +1,7 @@
 # vi: ts=4 expandtab syntax=sh
 
 # default imagesize = 2252*1024**2 = 2.2G (the current size we ship)
+# However this value may be overridden in individual hooks/binaries (like in buildd and ubuntu-cpc)
 imagesize=${IMAGE_SIZE:-2361393152}
 fs_label="${FS_LABEL:-rootfs}"
 
diff --git a/live-build/ubuntu-cpc/hooks.d/base/disk-image.binary b/live-build/ubuntu-cpc/hooks.d/base/disk-image.binary
index 63d28ab0..8b7206d4 100755
--- a/live-build/ubuntu-cpc/hooks.d/base/disk-image.binary
+++ b/live-build/ubuntu-cpc/hooks.d/base/disk-image.binary
@@ -14,6 +14,10 @@ ROOTPART_START=1
 
 my_d=$(dirname $(readlink -f ${0}))
 
+# NEW CPC default imagesize is 2.5G [2684354560 bytes] to avail of the slow increase in pkg sizes
+# This value will be passed into live-build/functions as an override
+imagesize=2684354560
+
 case $ARCH:$SUBARCH in
 	ppc64el:*|powerpc:*)
 		echo "POWER disk images are handled separately"
@@ -95,6 +99,7 @@ if [ "${should_install_grub}" -eq 1 ]; then
     echo "(hd0) ${loop_device}" > mountpoint/tmp/device.map
     # install the required package to get the grub-install command
     chroot mountpoint apt-get -qqy install --no-install-recommends grub-pc grub2-common
+    chroot mountpoint df --all --human-readable --print-type
     chroot mountpoint grub-install ${loop_device}
     chroot mountpoint grub-bios-setup \
         --boot-image=i386-pc/boot.img \