diff --git a/Makefile.defs b/Makefile.defs
index 8ad2e319f..d206611d3 100644
--- a/Makefile.defs
+++ b/Makefile.defs
@@ -24,6 +24,8 @@ CROSS  ?= arm-none-eabi-
 CC = gcc
 CXX = g++
 LD = g++
+SH = sh
+PERL = perl
 
 PATHSEP=/
 PREFIX ?=              /usr/local
diff --git a/armsrc/Makefile b/armsrc/Makefile
index 15cfaddfd..bc0fbc74b 100644
--- a/armsrc/Makefile
+++ b/armsrc/Makefile
@@ -155,7 +155,7 @@ showinfo:
 # version.c should be remade on every time fullimage.stage1.elf should be remade
 version.c: default_version.c $(OBJDIR)/fpga_version_info.o $(OBJDIR)/fpga_all.o $(THUMBOBJ) $(ARMOBJ)
 	$(info [-] GEN $@)
-	$(Q)sh ../tools/mkversion.sh > $@ || perl ../tools/mkversion.pl > $@ || $(CP) $^ $@
+	$(Q)$(SH) ../tools/mkversion.sh > $@ || $(PERL) ../tools/mkversion.pl > $@ || $(CP) $^ $@
 
 fpga_version_info.c: $(FPGA_BITSTREAMS) $(FPGA_COMPRESSOR)
 	$(info [-] GEN $@)
diff --git a/bootrom/Makefile b/bootrom/Makefile
index 676bd9a05..f6cf18174 100644
--- a/bootrom/Makefile
+++ b/bootrom/Makefile
@@ -39,7 +39,7 @@ OBJS = $(OBJDIR)/bootrom.s19
 # version.c should be remade on every compilation
 version.c: default_version.c
 	$(info [=] GEN $@)
-	$(Q)sh ../tools/mkversion.sh > $@ || perl ../tools/mkversion.pl > $@ || $(CP) $^ $@
+	$(Q)$(SH) ../tools/mkversion.sh > $@ || $(PERL) ../tools/mkversion.pl > $@ || $(CP) $^ $@
 
 all: showinfo $(OBJS)
 
diff --git a/client/Makefile b/client/Makefile
index 59685656b..33810b09b 100644
--- a/client/Makefile
+++ b/client/Makefile
@@ -430,7 +430,7 @@ zlib:
 # version.c should be remade on every compilation
 src/version.c: default_version.c
 	$(info [=] GEN $@)
-	$(Q)sh ../tools/mkversion.sh > $@ || perl ../tools/mkversion.pl > $@ || $(CP) $^ $@
+	$(Q)$(SH) ../tools/mkversion.sh > $@ || $(PERL) ../tools/mkversion.pl > $@
 
 # easy printing of MAKE VARIABLES
 print-%: ; @echo $* = $($*)