[openwrt/openwrt] mt7621: mikrotik: use vmlinuz (zBoot ELF)

[LEDE Commits]

981213 pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/254f51443ddaee873267d41993b5bbc4b5ef7959

commit 254f51443ddaee873267d41993b5bbc4b5ef7959
Author: John Thomson <git at johnthomson.fastmail.com.au>
AuthorDate: Thu Oct 15 19:27:55 2020 +1000

    mt7621: mikrotik: use vmlinuz (zBoot ELF)
    
    - minimal built initramfs: 11MB vmlinux ELF -> 4.5MB vmlinuz
    - ~5 seconds for kernel decompression, which was equivalent to the
      additional time to load the uncompressed ELF from SPI NOR.
    - Removes requirement for lzma-loader, which may have been causing some
      image builds to fail to boot on Mikrotik mt7621.
    
    Fixes: FS#3354
    Suggested-by: Thibaut VARÈNE <hacks at slashdirt.org>
    Signed-off-by: John Thomson <git at johnthomson.fastmail.com.au>
---
 target/linux/ramips/image/mt7621.mk  | 4 ++--
 target/linux/ramips/mt7621/target.mk | 3 +++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/target/linux/ramips/image/mt7621.mk b/target/linux/ramips/image/mt7621.mk
index 8919d764b0..bb7e5a0d48 100644
--- a/target/linux/ramips/image/mt7621.mk
+++ b/target/linux/ramips/image/mt7621.mk
@@ -708,8 +708,8 @@ define Device/MikroTik
   BLOCKSIZE := 64k
   IMAGE_SIZE := 16128k
   DEVICE_PACKAGES := kmod-usb3
-  LOADER_TYPE := elf
-  KERNEL := $(KERNEL_DTB) | loader-kernel
+  KERNEL_NAME := vmlinuz
+  KERNEL := kernel-bin | append-dtb-elf
   IMAGE/sysupgrade.bin := append-kernel | kernel2minor -s 1024 | \
 	pad-to $$$$(BLOCKSIZE) | append-rootfs | pad-rootfs | append-metadata | \
 	check-size
diff --git a/target/linux/ramips/mt7621/target.mk b/target/linux/ramips/mt7621/target.mk
index d05b8c82bf..d1f987b2e0 100644
--- a/target/linux/ramips/mt7621/target.mk
+++ b/target/linux/ramips/mt7621/target.mk
@@ -6,6 +6,9 @@ SUBTARGET:=mt7621
 BOARDNAME:=MT7621 based boards
 FEATURES+=nand ramdisk rtc usb minor
 CPU_TYPE:=24kc
+KERNELNAME:=vmlinux vmlinuz
+# make Kernel/CopyImage use $LINUX_DIR/vmlinuz
+IMAGES_DIR:=../../..
 
 DEFAULT_PACKAGES += wpad-basic-wolfssl