stage1, stage2: allow multiple kernels

sub.in/stage1/Makefile

@@ -21,8 +21,13 @@ include $(MKIMAGE_PREFIX)/targets.mk
 # here we try and come up with the installer kernel/modules, if any;
 # only a single kernel might be needed (STAGE1_KFLAVOUR sets explicitly);
 # kernel image copied from instrumental chroot into .work/syslinux/alt0/
+# Update: for grub allowed choose kernels
 
+ifeq (,$(filter-out x86_64 aarch64 ppc64le,$(ARCH)))
+STAGE1_KFLAVOUR ?= $(KFLAVOURS)
+else
 STAGE1_KFLAVOUR ?= $(lastword $(KFLAVOURS))
+endif
 
 # propagator needed iff stage1 kernel installed (not for e.g. syslinux.iso)
 ifneq "$(STAGE1_KFLAVOUR)" ""

sub.in/stage2/Makefile

@@ -29,7 +29,13 @@ IMAGE_PACKAGES += $(SYSTEM_PACKAGES) $(STAGE2_PACKAGES)
 
 # here we also try and come up with the stage1 kernel/modules, if any;
 # no kernel flavour specified will result in no modules for stage1 vmlinuz
+# Update: for grub allowed choose kernels
+
+ifeq (,$(filter-out x86_64 aarch64 ppc64le,$(ARCH)))
+STAGE1_KFLAVOUR ?= $(KFLAVOURS)
+else
 STAGE1_KFLAVOUR ?= $(lastword $(KFLAVOURS))
+endif
 
 ifeq (,$(STAGE1_KFLAVOUR))
 $(error STAGE1_KFLAVOUR is utterly empty; cannot guess either)