diff --git a/sdk/common.mk b/sdk/common.mk
index 98ed894..71b32ad 100644
--- a/sdk/common.mk
+++ b/sdk/common.mk
@@ -29,7 +29,7 @@ endif
 
 Z88DK		:= $(ZXSDK)/src/z88dk
 ZCCCFG		:= $(Z88DK)/lib/config
-PATH		:= $(ZXSDK_PLATFORM)/bin:$(Z88DK)/bin:$(PATH)
+PATH		:= $(ZXSDK_PLATFORM)/bin:$(Z88DK)/bin:$(ZXSDK):$(PATH)
 
 ifeq ($(OS),Windows_NT)
 PATH		:= $(ZXSDK_PLATFORM)/lib:$(PATH)
diff --git a/sdk/extract.sh b/sdk/extract.sh
new file mode 100755
index 0000000..47509e3
--- /dev/null
+++ b/sdk/extract.sh
@@ -0,0 +1,302 @@
+#!/bin/bash -e
+# extract.sh - extract contents of an archive.
+#
+# SPDX-FileCopyrightText: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+declare -a errors
+declare -A tmp_files
+declare o_input
+declare o_check=0
+declare o_sha256
+declare o_type
+declare o_subdir=.
+declare o_output
+declare o_use_tmp=0
+
+msg_err_begin() {
+	echo -en '\E[1;31m'
+}
+
+msg_err_end() {
+	echo -en '\E[0m'
+}
+
+# $1 = message
+add_error() {
+	errors[${#errors[@]}]="$1"
+}
+
+# $1 = argument name, $2 = argument index
+add_missing_arg_error() {
+	add_error "Missing parameter for '$1' (argument #$2)."
+}
+
+exit_on_errors() {
+	local -i i
+	local -i N
+	N=${#errors[@]}
+	if [[ $N -ne 0 ]]; then
+		msg_err_begin >&2
+		i=0
+		while [[ $i -lt $N ]]; do
+			echo "$BASH_SOURCE: Error ($((i+1))): ${errors[$i]}" >&2
+			let i=i+1
+		done
+		echo -n "$BASH_SOURCE: " >&2
+		if [[ $N -eq 1 ]]; then
+			echo -n "$N error occured." >&2
+		else
+			echo -n "$N errors occured." >&2
+		fi
+		echo " Stopped." >&2
+		msg_err_end >&2
+		exit 1
+	fi
+}
+
+# $1 = message (optional)
+error_exit() {
+	if [[ -n "$1" ]]; then
+		msg_err_begin >&2
+		echo "$1" >&2
+		msg_err_end >&2
+	fi
+	exit 1
+}
+
+# $1 = temporary file name
+new_tmp_file() {
+	tmp_files[$1]=f
+}
+
+# $1 = temporary directory name
+new_tmp_dir() {
+	tmp_files[$tmp]=d
+}
+
+# $1 = temporary file or directory name
+free_tmp() {
+	unset tmp_files[$1]
+}
+
+# $1 = temporary file name
+rm_tmp_file() {
+	rm -f "$1"
+	free_tmp "$1"
+}
+
+# $1 = temporary directory name
+rm_tmp_dir() {
+	rm -rf "$1"
+	free_tmp "$1"
+}
+
+rm_all_tmps() {
+	local t
+	if [[ ${#tmp_files[*]} -gt 0 ]]; then
+		OFS="$IFS"
+		IFS=`echo -en "\t"`
+		for t in ${!tmp_files[*]}; do
+			case ${tmp_files[$t]} in
+			f)
+				rm_tmp_file "$t"
+				;;
+			d)
+				rm_tmp_dir "$t"
+				;;
+			esac
+		done
+		IFS="$OFS"
+	fi
+}
+
+show_usage() {
+	cat <<EOT
+Usage:
+  $BASH_SOURCE [--sha256 SHA256] --type TYPE [--subdir SUBDIR] --output DIR [--use-tmp-dir] [--] input_file
+Where:
+  --sha256 SHA256	check SHA256 message digest of input file
+  --type TYPE		type of input archive (.zip, .tar.gz, .tar.bz2, .7z)
+  --subdir SUBDIR	specify SUBDIR sub-directory of input file to strip
+  --output DIR		specify output directory
+  --use-tmp-dir		use temporary directory
+EOT
+}
+
+OnError() {
+	local err=$?
+	msg_err_begin >&2
+	echo "$BASH_SOURCE: Error on line $BASH_LINENO: Exit status $err. Stopped." >&2
+	msg_err_end >&2
+	exit $err
+}
+
+OnExit() {
+	rm_all_tmps
+}
+
+trap OnError ERR
+trap OnExit EXIT
+
+if [[ $# -eq 0 ]]; then
+	show_usage
+	exit
+fi
+
+parse_option=1
+i=1
+while [[ $# -gt 0 ]]; do
+	non_option=0
+	if [[ $parse_option -eq 1 ]]; then
+		case "$1" in
+		--sha256)
+			if [[ $# -eq 1 ]]; then
+				add_missing_arg_error $1 $i
+				break
+			fi
+			o_check=1
+			o_sha256=$2
+			shift 2
+			let i=i+1
+			;;
+		--type)
+			if [[ $# -eq 1 ]]; then
+				add_missing_arg_error $1 $i
+				break
+			fi
+			case "$2" in
+			.zip|.tar.gz|.tar.bz2|.7z)
+				o_type=$2
+				;;
+			*)
+				add_error "Unknown archive type specified: '$2' (argument #$((i+1)))."
+				;;
+			esac
+			shift 2
+			let i=i+1
+			;;
+		--subdir)
+			if [[ $# -eq 1 ]]; then
+				add_missing_arg_error $1 $i
+				break
+			fi
+			o_subdir=$2
+			shift 2
+			let i=i+1
+			;;
+		--output)
+			if [[ $# -eq 1 ]]; then
+				add_missing_arg_error $1 $i
+				break
+			fi
+			o_output=$2
+			shift 2
+			let i=i+1
+			;;
+		--use-tmp-dir)
+			o_use_tmp=1
+			shift 1
+			;;
+		--)
+			parse_option=0
+			shift 1
+			;;
+		-*)
+			add_error "Unknown option '$1' (argument #$i)."
+			shift 1
+			;;
+		*)
+			non_option=1
+			;;
+		esac
+	else
+		non_option=1
+	fi
+	if [[ $non_option -eq 1 ]]; then
+		if [[ -z "$o_input" ]]; then
+			o_input="$1"
+		else
+			add_error "Extra input file specified: '$1' (argument #$i)."
+		fi
+		shift 1
+	fi
+	let i=i+1
+done
+
+if [[ -z "$o_input" ]]; then
+	add_error "No input file specified."
+fi
+
+if [[ -z "$o_type" ]]; then
+	add_error "No input file type specified."
+fi
+
+if [[ -z "$o_output" ]]; then
+	add_error "No output directory specified."
+fi
+
+#~ echo "$BASH_SOURCE: o_input:   \"$o_input\""
+#~ echo "$BASH_SOURCE: o_check:   $o_check"
+#~ echo "$BASH_SOURCE: o_sha256:  \"$o_sha256\""
+#~ echo "$BASH_SOURCE: o_type:    \"$o_type\""
+#~ echo "$BASH_SOURCE: o_subdir:  \"$o_subdir\""
+#~ echo "$BASH_SOURCE: o_output:  \"$o_output\""
+#~ echo "$BASH_SOURCE: o_use_tmp: $o_use_tmp"
+
+exit_on_errors
+
+tmp=`mktemp`
+new_tmp_file "$tmp"
+echo "$o_sha256  $o_input" >"$tmp"
+sha256sum -c "$tmp"
+rm_tmp_file "$tmp"
+
+if [[ $o_use_tmp -eq 0 ]]; then
+	if [[ "$o_subdir" != "$o_output" && "$o_subdir" != '.' ]]; then
+		rm -rf "$o_subdir"
+	fi
+	case "$o_type" in
+	.zip)
+		if [[ "$o_subdir" = '.' ]]; then
+			unzip -nq -d "$o_output" "$o_input"
+		else
+			unzip -nq "$o_input"
+		fi
+		;;
+	.tar.gz)
+		if [[ "$o_subdir" = '.' ]]; then
+			add_error "Not implemented for '$o_type': subdir='$o_subdir'."
+			exit_on_errors
+		else
+			tar -xzf "$o_input"
+		fi
+		;;
+	.tar.bz2)
+		if [[ "$o_subdir" = '.' ]]; then
+			add_error "Not implemented for '$o_type': subdir='$o_subdir'."
+			exit_on_errors
+		else
+			tar -xjf "$o_input"
+		fi
+		;;
+	.7z)
+		if [[ "$o_subdir" = '.' ]]; then
+			7z x -bd -o "$o_output" "$o_input"
+		else
+			7z x -bd "$o_input"
+		fi
+		;;
+	*)
+		add_error "Not supported archive type: '$o_type'."
+		exit_on_errors
+		;;
+	esac
+	if [[ "$o_subdir" != "$o_output" && "$o_subdir" != '.' ]]; then
+		mv "$o_subdir" "$o_output"
+	fi
+else
+	add_error "Temporary directory usage is not implemented yet."
+	exit_on_errors
+fi
diff --git a/sdk/setenv.sh b/sdk/setenv.sh
index 6352b70..8a2cc9e 100644
--- a/sdk/setenv.sh
+++ b/sdk/setenv.sh
@@ -12,7 +12,7 @@ if [[ "x$ZXSDK" == x ]]; then
 	fi
 	Z88DK=$ZXSDK/src/z88dk
 	ZCCCFG=$Z88DK/lib/config
-	PATH=$ZXSDK_PLATFORM/bin:$Z88DK/bin:$PATH
+	PATH=$ZXSDK_PLATFORM/bin:$Z88DK/bin:$ZXSDK:$PATH
 	if [[ x$OS == xWindows_NT ]]; then
 		PATH=$ZXSDK_PLATFORM/lib:$PATH
 		# Fix paths under Cygwin for z88dk on Windows
diff --git a/sdk/src/sjasmplus-z00m128.inc.mk b/sdk/src/sjasmplus-z00m128.inc.mk
index e00fca0..6ad1375 100644
--- a/sdk/src/sjasmplus-z00m128.inc.mk
+++ b/sdk/src/sjasmplus-z00m128.inc.mk
@@ -22,21 +22,12 @@ build-sjasmplus: | sjasmplus-z00m128/.extracted sjasmplus-z00m128.mk
 	$(MAKE) -w -C sjasmplus -f ../sjasmplus-z00m128.mk prefix=$(shell realpath --relative-to=sjasmplus-z00m128 $(prefix))
 
 sjasmplus-z00m128/.extracted: $(SJASMPLUS_ARCHIVE)
-	echo '$(SJASMPLUS_ARCHIVE_SHA256)  $<' >$<.sha256
-	sha256sum -c $<.sha256
-	rm -f $<.sha256
 	rm -rf $(@D)
-	test '$(@D)' = '$(SJASMPLUS_ARCHIVE_SUBDIR)' -o '$(SJASMPLUS_ARCHIVE_SUBDIR)' = . || rm -rf $(SJASMPLUS_ARCHIVE_SUBDIR)
-ifeq ($(SJASMPLUS_ARCHIVE_TYPE),.tar.gz)
- ifeq ($(SJASMPLUS_ARCHIVE_SUBDIR),.)
-  $(error Not implemented)
- else
-	tar -xzf $<
- endif
-else
- $(error Not implemented)
-endif
-	test '$(@D)' = '$(SJASMPLUS_ARCHIVE_SUBDIR)' -o '$(SJASMPLUS_ARCHIVE_SUBDIR)' = . || mv $(SJASMPLUS_ARCHIVE_SUBDIR) $(@D)
+	extract.sh $<\
+	 --sha256 $(SJASMPLUS_ARCHIVE_SHA256)\
+	 --type $(SJASMPLUS_ARCHIVE_TYPE)\
+	 --subdir $(SJASMPLUS_ARCHIVE_SUBDIR)\
+	 --output $(@D)
 	touch $@
 
 .downloads/sjasmplus-z00m128/v1.18.2.tar.gz: | .downloads/sjasmplus-z00m128
@@ -83,21 +74,12 @@ SJASMPLUS_ARCHIVE_TYPE		= .zip
 SJASMPLUS_ARCHIVE_SUBDIR	= sjasmplus-1.18.2.win
 
 sjasmplus-z00m128/.extracted: $(SJASMPLUS_ARCHIVE)
-	echo '$(SJASMPLUS_ARCHIVE_SHA256)  $<' >$<.sha256
-	sha256sum -c $<.sha256
-	rm -f $<.sha256
 	rm -rf $(@D)
-	test '$(@D)' = '$(SJASMPLUS_ARCHIVE_SUBDIR)' -o '$(SJASMPLUS_ARCHIVE_SUBDIR)' = . || rm -rf $(SJASMPLUS_ARCHIVE_SUBDIR)
-ifeq ($(SJASMPLUS_ARCHIVE_TYPE),.zip)
- ifeq ($(SJASMPLUS_ARCHIVE_SUBDIR),.)
-	unzip -nq -d $(@D) $<
- else
-	unzip -nq $<
- endif
-else
- $(error Not implemented)
-endif
-	test '$(@D)' = '$(SJASMPLUS_ARCHIVE_SUBDIR)' -o '$(SJASMPLUS_ARCHIVE_SUBDIR)' = . || mv $(SJASMPLUS_ARCHIVE_SUBDIR) $(@D)
+	extract.sh $<\
+	 --sha256 $(SJASMPLUS_ARCHIVE_SHA256)\
+	 --type $(SJASMPLUS_ARCHIVE_TYPE)\
+	 --subdir $(SJASMPLUS_ARCHIVE_SUBDIR)\
+	 --output $(@D)
 	touch $@
 
 .downloads/sjasmplus-z00m128/sjasmplus-1.18.2.win.zip: | .downloads/sjasmplus-z00m128
diff --git a/sdk/src/sjasmplus.inc.mk b/sdk/src/sjasmplus.inc.mk
index 3096f26..2a0efb5 100644
--- a/sdk/src/sjasmplus.inc.mk
+++ b/sdk/src/sjasmplus.inc.mk
@@ -22,21 +22,12 @@ build-sjasmplus: | sjasmplus/.extracted sjasmplus.mk
 	$(MAKE) -w -C sjasmplus -f ../sjasmplus.mk prefix=$(shell realpath --relative-to=sjasmplus $(prefix))
 
 sjasmplus/.extracted: $(SJASMPLUS_ARCHIVE)
-	echo '$(SJASMPLUS_SHA256)  $<' >$<.sha256
-	sha256sum -c $<.sha256
-	rm -f $<.sha256
 	rm -rf $(@D)
-	test '$(@D)' = '$(SJASMPLUS_ARCHIVE_SUBDIR)' -o '$(SJASMPLUS_ARCHIVE_SUBDIR)' = . || rm -rf $(SJASMPLUS_ARCHIVE_SUBDIR)
-ifeq ($(SJASMPLUS_ARCHIVE_TYPE),.tar.gz)
- ifeq ($(SJASMPLUS_ARCHIVE_SUBDIR),.)
-  $(error Not implemented)
- else
-	tar -xzf $<
- endif
-else
- $(error Not implemented)
-endif
-	test '$(@D)' = '$(SJASMPLUS_ARCHIVE_SUBDIR)' -o '$(SJASMPLUS_ARCHIVE_SUBDIR)' = . || mv $(SJASMPLUS_ARCHIVE_SUBDIR) $(@D)
+	extract.sh $<\
+	 --sha256 $(SJASMPLUS_ARCHIVE_SHA256)\
+	 --type $(SJASMPLUS_ARCHIVE_TYPE)\
+	 --subdir $(SJASMPLUS_ARCHIVE_SUBDIR)\
+	 --output $(@D)
 	touch $@
 
 .downloads/sjasmplus/20190306.1.tar.gz: | .downloads/sjasmplus
@@ -94,21 +85,12 @@ else
 endif
 
 sjasmplus/.extracted: $(SJASMPLUS_ARCHIVE)
-	echo '$(SJASMPLUS_ARCHIVE_SHA256)  $<' >$<.sha256
-	sha256sum -c $<.sha256
-	rm -f $<.sha256
 	rm -rf $(@D)
-	test '$(@D)' = '$(SJASMPLUS_ARCHIVE_SUBDIR)' -o '$(SJASMPLUS_ARCHIVE_SUBDIR)' = . || rm -rf $(SJASMPLUS_ARCHIVE_SUBDIR)
-ifeq ($(SJASMPLUS_ARCHIVE_TYPE),.7z)
- ifeq ($(SJASMPLUS_ARCHIVE_SUBDIR),.)
-	7z x -bd -o$(@D) $<
- else
-	7z x -bd $<
- endif
-else
- $(error Not implemented)
-endif
-	test '$(@D)' = '$(SJASMPLUS_ARCHIVE_SUBDIR)' -o '$(SJASMPLUS_ARCHIVE_SUBDIR)' = . || mv $(SJASMPLUS_ARCHIVE_SUBDIR) $(@D)
+	extract.sh $<\
+	 --sha256 $(SJASMPLUS_ARCHIVE_SHA256)\
+	 --type $(SJASMPLUS_ARCHIVE_TYPE)\
+	 --subdir $(SJASMPLUS_ARCHIVE_SUBDIR)\
+	 --output $(@D)
 	touch $@
 
 .downloads/sjasmplus/sjasmplus-win32-20190306.1.7z: | .downloads/sjasmplus
diff --git a/sdk/src/z88dk.inc.mk b/sdk/src/z88dk.inc.mk
index ad50b3b..9b769ca 100644
--- a/sdk/src/z88dk.inc.mk
+++ b/sdk/src/z88dk.inc.mk
@@ -53,21 +53,12 @@ z88dk/.done: | z88dk/.extracted z88dk.mk
 	touch $@
 
 z88dk/.extracted: $(Z88DK_ARCHIVE) | z88dk.patch
-	echo '$(Z88DK_ARCHIVE_SHA256)  $<' >$<.sha256
-	sha256sum -c $<.sha256
-	rm -f $<.sha256
 	rm -rf $(@D)
-	test '$(@D)' = '$(Z88DK_ARCHIVE_SUBDIR)' -o '$(Z88DK_ARCHIVE_SUBDIR)' = . || rm -rf $(Z88DK_ARCHIVE_SUBDIR)
-ifeq ($(Z88DK_ARCHIVE_TYPE),.tar.gz)
- ifeq ($(Z88DK_ARCHIVE_SUBDIR),.)
-  $(error Not implemented)
- else
-	tar -xzf $<
- endif
-else
- $(error Not implemented)
-endif
-	test '$(@D)' = '$(Z88DK_ARCHIVE_SUBDIR)' -o '$(Z88DK_ARCHIVE_SUBDIR)' = . || mv $(Z88DK_ARCHIVE_SUBDIR) $(@D)
+	extract.sh $<\
+	 --sha256 $(Z88DK_ARCHIVE_SHA256)\
+	 --type $(Z88DK_ARCHIVE_TYPE)\
+	 --subdir $(Z88DK_ARCHIVE_SUBDIR)\
+	 --output $(@D)
 	patch -N -p0 -s <$| || true
 	touch $@
 
@@ -106,21 +97,12 @@ Z88DK_ARCHIVE_TYPE	= .zip
 Z88DK_ARCHIVE_SUBDIR	= z88dk
 
 z88dk/.done: $(Z88DK_ARCHIVE)
-	echo '$(Z88DK_ARCHIVE_SHA256)  $<' >$<.sha256
-	sha256sum -c $<.sha256
-	rm -f $<.sha256
 	rm -rf $(@D)
-	test '$(@D)' = '$(Z88DK_ARCHIVE_SUBDIR)' -o '$(Z88DK_ARCHIVE_SUBDIR)' = . || rm -rf $(Z88DK_ARCHIVE_SUBDIR)
-ifeq ($(Z88DK_ARCHIVE_TYPE),.zip)
- ifeq ($(Z88DK_ARCHIVE_SUBDIR),.)
-	unzip -nq -d $(@D) $<
- else
-	unzip -nq $<
- endif
-else
- $(error Not implemented)
-endif
-	test '$(@D)' = '$(Z88DK_ARCHIVE_SUBDIR)' -o '$(Z88DK_ARCHIVE_SUBDIR)' = . || mv $(Z88DK_ARCHIVE_SUBDIR) $(@D)
+	extract.sh $<\
+	 --sha256 $(Z88DK_ARCHIVE_SHA256)\
+	 --type $(Z88DK_ARCHIVE_TYPE)\
+	 --subdir $(Z88DK_ARCHIVE_SUBDIR)\
+	 --output $(@D)
 	touch $@
 
 .downloads/z88dk/z88dk-win32-2.1.zip: | .downloads/z88dk