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

debian/changelog

@@ -1,3 +1,11 @@
+livecd-rootfs (2.558) UNRELEASED; urgency=medium
+
+  * Use the new linux-firmware-raspi2 for pi3 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 17:09:26 +0100
+
 livecd-rootfs (2.557) disco; urgency=medium
 
   * Don't install gpg or gpg-agent when building buildd images for series

live-build/auto/config

@@ -834,7 +834,7 @@ 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
 				;;