diff --git a/Makefile b/Makefile
index f187ddf..c1a93c6 100644
--- a/Makefile
+++ b/Makefile
@@ -186,10 +186,10 @@
 # Only keep -O and -g cflags
 .PHONY: $(ROM_DIRS_RULES)
 $(ROM_DIRS_RULES):
-	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C $(dir $@) V="$(V)" TARGET_DIR="$(dir $@)" CFLAGS="$(filter -O% -g%,$(CFLAGS))" $(notdir $@),)
+	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C $(dir $@) V="$(V)" TARGET_DIR="$(dir $@)" $(notdir $@),)
 
 .PHONY: recurse-all recurse-clean
-recurse-all: $(ROM_DIRS)
+recurse-all: $(addsuffix /all, $(ROM_DIRS))
 recurse-clean: $(addsuffix /clean, $(ROM_DIRS))
 
 ######################################################################
diff --git a/pc-bios/optionrom/Makefile b/pc-bios/optionrom/Makefile
index 51cb6ca..084fc10 100644
--- a/pc-bios/optionrom/Makefile
+++ b/pc-bios/optionrom/Makefile
@@ -8,15 +8,12 @@
 	@true
 
 include ../../config-host.mak
+CFLAGS = -O2 -g
 
 quiet-command = $(if $(V),$1,$(if $(2),@printf "  %-7s %s\n" $2 $3 && $1, @$1))
-cc-option = $(if $(shell $(CC) $1 -S -o /dev/null -xc /dev/null >/dev/null 2>&1 && echo OK), $1, $2)
+cc-option = $(if $(shell $(CC) $1 -c -o /dev/null -xc /dev/null >/dev/null 2>&1 && echo OK), $1, $2)
 
-# Compiling with no optimization creates ROMs that are too large
-ifeq ($(lastword $(filter -O%, -O0 $(CFLAGS))),-O0)
-override CFLAGS += -O2
-endif
-override CFLAGS += -march=i486
+override CFLAGS += -march=i486 -Wall
 
 # Flags for dependency generation
 override CPPFLAGS += -MMD -MP -MT $@ -MF $(@D)/$(*F).d
@@ -42,7 +39,6 @@
 override ASFLAGS += -32
 override CFLAGS += $(call cc-option, $(Wa)-32)
 
-
 LD_I386_EMULATION ?= elf_i386
 override LDFLAGS = -m $(LD_I386_EMULATION) -T $(SRC_DIR)/flat.lds
 override LDFLAGS += $(LDFLAGS_NOPIE)
diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
index cc0f77b..3eb7850 100644
--- a/pc-bios/s390-ccw/Makefile
+++ b/pc-bios/s390-ccw/Makefile
@@ -3,6 +3,7 @@
 	@true
 
 include ../../config-host.mak
+CFLAGS = -O2 -g
 
 quiet-command = $(if $(V),$1,$(if $(2),@printf "  %-7s %s\n" $2 $3 && $1, @$1))
 cc-option = $(if $(shell $(CC) $1 -S -o /dev/null -xc /dev/null > /dev/null \
@@ -28,7 +29,7 @@
 OBJECTS = start.o main.o bootmap.o jump2ipl.o sclp.o menu.o \
 	  virtio.o virtio-scsi.o virtio-blkdev.o libc.o cio.o dasd-ipl.o
 
-QEMU_CFLAGS := $(filter -W%, $(QEMU_CFLAGS))
+QEMU_CFLAGS := -Wall $(filter -W%, $(QEMU_CFLAGS))
 QEMU_CFLAGS += -ffreestanding -fno-delete-null-pointer-checks -msoft-float
 QEMU_CFLAGS += -march=z900 -fPIE -fno-strict-aliasing
 QEMU_CFLAGS += -fno-asynchronous-unwind-tables