Use linux-firmware-raspi2 instead of raspi3-firmware.

debian/changelog

@@ -3,6 +3,9 @@ livecd-rootfs (2.525.14) UNRELEASED; urgency=medium
   * More changes for raspi3 build support (LP: #1805668):
     - Fix 100-purge-grub-legacy-ec2-arm.chroot to not gate on ARCH as that's
       not defined in .chroot hooks.
+    - Use the new linux-firmware-raspi2 for boot binary blobs as
+      raspi3-firmware includes upgrade hooks that conflict with our image
+      configuration.
 
  -- Łukasz 'sil2100' Zemczak <lukasz.zemczak@ubuntu.com>  Fri, 18 Jan 2019 16:56:58 +0100
 

live-build/auto/config

@@ -817,7 +817,7 @@ case $ARCH in
 			raspi3)
 				COMPONENTS='main restricted universe multiverse'
 				KERNEL_FLAVOURS=raspi2
-				add_package install raspi3-firmware u-boot-rpi flash-kernel u-boot-tools wpasupplicant
+				add_package install linux-firmware-raspi2 u-boot-rpi flash-kernel u-boot-tools wpasupplicant
 				BINARY_REMOVE_LINUX=false
 				;;