diff --git a/Makefile b/Makefile
index 7b02406..60a39e5 100644
--- a/Makefile
+++ b/Makefile
@@ -1,17 +1,27 @@
 # Updates content of SD directory.
 #
+# SPDX-FileCopyrightText: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
 # Supported environments:
 #   * GNU on Linux, FreeBSD etc.
 #   * GNU on Windows NT (using MinGW/MSYS/Cygwin/WSL)
 #
-# Build:
-#   make
+# Build the project:
+#   make [all]
+# Compile only:
+#   make build | build-<TARGET>
+# Install:
+#   make install | install-<TARGET>
+# Uninstall:
+#   make uninstall | uninstall-<TARGET>
 # Clean:
-#   make clean
+#   make clean | clean-<TARGET>
+#   make distclean | distclean-<TARGET>
 #
-# SPDX-FileCopyrightText: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
-#
-# SPDX-License-Identifier: GPL-3.0-or-later
+# where:
+#   <TARGET> is one of the values for `TARGETS' variable.
 
 include sdk/common.mk
 
@@ -20,65 +30,75 @@ prefix		?= SD
 exec_prefix	?= $(prefix)
 bindir		?= $(exec_prefix)/BIN
 
-INSTALL		?= install
-INSTALL_PROGRAM	?= $(INSTALL)
-RM		= rm -f
+TARGETS=\
+ utils\
+ software
 
-SOFTWARE_TARGETS=\
- ESPRST\
- IWCONFIG
+SOFTWARE_SUBDIRS=\
+ esprst\
+ iwconfig
 
 .PHONY: all
-all:\
- install-utils\
- install-software
+all: $(foreach t,$(TARGETS),install-$(t))
 	@echo 'Done.'
 
 # utils
 
+.PHONY: build-utils
+build-utils: | utils
+	$(MAKE) -w -C $| bindir=$(shell realpath --relative-to=$| $(bindir))
+
 .PHONY: install-utils
 install-utils: | utils
 	$(MAKE) -w -C $| bindir=$(shell realpath --relative-to=$| $(bindir)) install
 
+.PHONY: uninstall-utils
+uninstall-utils: | utils
+	$(MAKE) -w -C $| bindir=$(shell realpath --relative-to=$| $(bindir)) uninstall
+
 .PHONY: clean-utils
 clean-utils: | utils
 	$(MAKE) -w -C $| clean
 
-.PHONY: uninstall-utils
-uninstall-utils: clean-utils | utils
-	$(MAKE) -w -C $| bindir=$(shell realpath --relative-to=$| $(bindir)) uninstall
+.PHONY: distclean-utils
+distclean-utils: | utils
+	$(MAKE) -w -C $| distclean
 
 # software
 
+.PHONY: build-software
+build-software: | software
+	$(MAKE) -w -C $| bindir=$(shell realpath --relative-to=$| $(bindir))
+
 .PHONY: install-software
-install-software: $(foreach t,$(SOFTWARE_TARGETS),$(DESTDIR)$(bindir)/$(t))
-
-$(DESTDIR)$(bindir)/ESPRST: software/esprst/esprst
-	$(INSTALL) $< $@
-
-$(DESTDIR)$(bindir)/IWCONFIG: software/iwconfig/IWCONFIG
-	$(INSTALL) $< $@
-
-software/esprst/esprst: | software/esprst
-	$(MAKE) -w -C $|
-
-software/iwconfig/IWCONFIG: | software/iwconfig
-	$(MAKE) -w -C $|
-
-.PHONY: clean-software
-clean-software: |\
- software/esprst\
- software/iwconfig
-	$(MAKE) -w -C software/esprst clean
-	$(MAKE) -w -C software/iwconfig clean
+install-software: | software
+	for d in $(SOFTWARE_SUBDIRS); do d=$|/$$d; $(MAKE) -w -C $$d bindir=$$(realpath --relative-to=$$d $(bindir)) install; done
 
 .PHONY: uninstall-software
-uninstall-software: clean-software
-	$(RM) $(foreach t,$(SOFTWARE_TARGETS),$(DESTDIR)$(bindir)/$(t))
+uninstall-software: | software
+	for d in $(SOFTWARE_SUBDIRS); do d=$|/$$d; $(MAKE) -w -C $$d bindir=$$(realpath --relative-to=$$d $(bindir)) uninstall; done
 
-# clean
+.PHONY: clean-software
+clean-software: | software
+	for d in $(SOFTWARE_SUBDIRS); do d=$|/$$d; $(MAKE) -w -C $$d bindir=$$(realpath --relative-to=$$d $(bindir)) clean; done
+
+.PHONY: distclean-software
+distclean-software: | software
+	for d in $(SOFTWARE_SUBDIRS); do d=$|/$$d; $(MAKE) -w -C $$d bindir=$$(realpath --relative-to=$$d $(bindir)) distclean; done
+
+# all
+
+.PHONY: build
+build: $(foreach t,$(TARGETS),build-$(t))
+
+.PHONY: install
+install: $(foreach t,$(TARGETS),install-$(t))
+
+.PHONY: uninstall
+uninstall: $(foreach t,$(TARGETS),uninstall-$(t))
 
 .PHONY: clean
-clean:\
- uninstall-utils\
- uninstall-software
+clean: $(foreach t,$(TARGETS),clean-$(t))
+
+.PHONY: distclean
+distclean: $(foreach t,$(TARGETS),distclean-$(t))
diff --git a/firmware/bootloader.asm b/firmware/bootloader.asm
index 916f492..9e0acb2 100644
--- a/firmware/bootloader.asm
+++ b/firmware/bootloader.asm
@@ -1,17 +1,42 @@
+; firmware.asm
+;
+; Copyright (C) 2016-2021 Antonio Villena
+; Contributors:
+;   2015 Einar Saukas (ZX7 Backwards)
+;   2021 Ivan Tatarinov <ivan-tat@ya.ru>
+;
+; This program is free software: you can redistribute it and/or modify
+; it under the terms of the GNU General Public License as published by
+; the Free Software Foundation, version 3.
+;
+; This program is distributed in the hope that it will be useful,
+; but WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+; GNU General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program. If not, see <https://www.gnu.org/licenses/>.
+;
+; SPDX-FileCopyrightText: Copyright (C) 2016-2021 Antonio Villena
+;
+; SPDX-FileContributor: 2015 Einar Saukas (ZX7 Backwards)
+; SPDX-FileContributor: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
+;
+; SPDX-License-Identifier: GPL-3.0-only
+
+; Compatible compilers:
+;   SJAsmPlus, <https://github.com/sjasmplus/sjasmplus/>
+;   SJAsmPlus by aprisobal, <https://github.com/z00m128/sjasmplus/>
+
+        output  bootloader.rom
+
+        include zxuno.def
+
       macro wreg  dir, dato
         rst     $28
         defb    dir, dato
       endm
 
-        output  bootloader.rom
-        define  zxuno_port      $fc3b
-        define  master_conf     0
-        define  master_mapper   1
-        define  flash_spi       2
-        define  flash_cs        3
-        define  joyconf         6
-        define  scandbl_ctrl    11
-
         di
         ld      sp, $bfff-ini+6
         wreg    flash_cs, 1     ; desactivamos spi, enviando un 0
@@ -51,7 +76,7 @@ nmi66   jp      $c003
         retn
 
 cont    wreg    flash_cs, 1     ; desactivamos spi, enviando un 1
-        wreg    joyconf, %00010000
+        wreg    joy_conf, %00010000
         wreg    master_mapper, 8  ; paginamos la ROM en $c000
 lee     in      a, ($1f)
         djnz    lee
@@ -85,10 +110,10 @@ recov   ld      hl, firmware-1
         block   $0100 - $
         include scroll/define.asm
         ld      sp, 0
-        ld      de, $5e6d+filesize-1
+        ld      de, filestart+filesize-1
         ld      hl, scroll-1
         call    dzx7b
-        jp      $7be4
+        jp      start
 
 ; -----------------------------------------------------------------------------
 ; ZX7 Backwards by Einar Saukas, Antonio Villena
diff --git a/software/esprst/.gitignore b/software/esprst/.gitignore
index f8cb13a..7cef27e 100644
--- a/software/esprst/.gitignore
+++ b/software/esprst/.gitignore
@@ -2,4 +2,4 @@
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-esprst
+build
diff --git a/software/esprst/Makefile b/software/esprst/Makefile
index a93b5b1..c589414 100644
--- a/software/esprst/Makefile
+++ b/software/esprst/Makefile
@@ -1,15 +1,82 @@
 # SPDX-FileCopyrightText: Copyright (C) 2019 Alexander Sharikhin
 #
+# SPDX-FileContributor: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
+#
 # SPDX-License-Identifier: GPL-3.0-or-later
+#
+# Supported environments:
+#   * GNU on Linux, FreeBSD etc.
+#   * GNU on Windows NT (using MinGW/MSYS/Cygwin/WSL)
+#
+# Build:
+#   make [<TARGET> ...]
+# Install / Uninstall:
+#   make [prefix=<PREFIX>] install | uninstall
+# Clean:
+#   make clean | distclean
+#
+# where:
+#   <TARGET> is one of values for `BINS' variable prefixed with "build/"
+#     (see target `all' below).
+#   <PREFIX> is a prefix directory to install files into.
 
 include ../../sdk/common.mk
 
-.PHONY: all
-all: esprst
+# Use uppercase for FAT filesystem
+srcdir		= .
+prefix		?= .
+exec_prefix	?= $(prefix)
+bindir		?= $(exec_prefix)/BIN
 
-esprst: main.asm uart.asm ring.asm
-	sjasmplus $<
+# Disable execution mode for FAT filesystem
+INSTALL		?= install
+INSTALL_PROGRAM	?= $(INSTALL) -m 644
+RM		= rm -f
+
+AS		= sjasmplus
+ifeq ($(USE_SJASMPLUS_VERSION),sjasmplus)
+AFLAGS		= --nobanner
+else ifeq ($(USE_SJASMPLUS_VERSION),z00m128)
+AFLAGS		= --nologo
+else
+AFLAGS		=
+endif
+
+BINS=\
+ ESPRST
+
+.PHONY: all
+all: $(foreach t,$(BINS),build/$(t))
+
+build\
+$(DESTDIR)$(bindir):
+	mkdir -p $@
+
+build/ESPRST: $(srcdir)/main.asm\
+ $(srcdir)/uart.asm\
+ $(srcdir)/ring.asm\
+ | build
+	$(AS) $(AFLAGS) --raw=$@ $<
+
+# $1 = target
+define install_bin_rule =
+$$(DESTDIR)$$(bindir)/$1: build/$1 | $$(DESTDIR)$$(bindir)
+	$$(INSTALL_PROGRAM) $$< $$@
+endef
+
+$(foreach t,$(BINS),$(eval $(call install_bin_rule,$(t))))
+
+.PHONY: install
+install: $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
+
+.PHONY: uninstall
+uninstall:
+	$(RM) $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
 
 .PHONY: clean
 clean:
-	rm -f esprst
+	rm -f $(foreach t,$(BINS),build/$(t))
+
+.PHONY: distclean
+distclean:
+	rm -rf build/*
diff --git a/software/esprst/main.asm b/software/esprst/main.asm
index 0b55662..901f00e 100644
--- a/software/esprst/main.asm
+++ b/software/esprst/main.asm
@@ -90,4 +90,4 @@ cmd_info    defb "AT+GMR", 13, 10, 0
 response_ok defb "OK", 13, 10, 0
 response_er defb "ready", 0
 
-    SAVEBIN "esprst", Start, $ - Start
+;   SAVEBIN "esprst", Start, $ - Start
diff --git a/software/iwconfig/.gitignore b/software/iwconfig/.gitignore
index 3fd67f3..7cef27e 100644
--- a/software/iwconfig/.gitignore
+++ b/software/iwconfig/.gitignore
@@ -2,6 +2,4 @@
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-*.bin
-*.def
-IWCONFIG
+build
diff --git a/software/iwconfig/Makefile b/software/iwconfig/Makefile
index 4757207..596c2ee 100644
--- a/software/iwconfig/Makefile
+++ b/software/iwconfig/Makefile
@@ -1,15 +1,74 @@
 # SPDX-FileCopyrightText: Copyright (C) 2019 Alexander Sharikhin
 #
+# SPDX-FileContributor: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
+#
 # SPDX-License-Identifier: GPL-3.0-or-later
+#
+# Supported environments:
+#   * GNU on Linux, FreeBSD etc.
+#   * GNU on Windows NT (using MinGW/MSYS/Cygwin/WSL)
+#
+# Build:
+#   make [<TARGET> ...]
+# Install / Uninstall:
+#   make [prefix=<PREFIX>] install | uninstall
+# Clean:
+#   make clean | distclean
+#
+# where:
+#   <TARGET> is one of values for `BINS' variable prefixed with "build/"
+#     (see target `all' below).
+#   <PREFIX> is a prefix directory to install files into.
 
 include ../../sdk/common.mk
 
-.PHONY: all
-all: IWCONFIG
+# Use uppercase for FAT filesystem
+srcdir		= .
+prefix		?= .
+exec_prefix	?= $(prefix)
+bindir		?= $(exec_prefix)/BIN
 
-IWCONFIG: iwconfig.c
-	zcc +zx -vn -startup=30 -clib=new $< -SO3 -o $@ -subtype=dot -create-app
+# Disable execution mode for FAT filesystem
+INSTALL		?= install
+INSTALL_PROGRAM	?= $(INSTALL) -m 644
+RM		= rm -f
+
+BINS=\
+ IWCONFIG
+
+# `zcc' compiler's behavior:
+#   * produces binary file in source's directory only
+#   * creates temporary files
+TMPS=\
+ $(foreach t,$(BINS),$(t)_CODE.bin $(t)_UNASSIGNED.bin)
+
+.PHONY: all
+all: $(foreach t,$(BINS),build/$(t))
+
+build\
+$(DESTDIR)$(bindir):
+	mkdir -p $@
+
+build/IWCONFIG: $(srcdir)/iwconfig.c | build
+	zcc +zx -vn -startup=30 -clib=new $< -SO3 -o $(@F) -subtype=dot -create-app
+# Workaround for zcc:
+	rm -f $(TMPS)
+	mv $(@F) $@
+
+$(DESTDIR)$(bindir)/%: build/% | $(DESTDIR)$(bindir)
+	cp $< $@
+
+.PHONY: install
+install: $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
+
+.PHONY: uninstall
+uninstall:
+	$(RM) $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
 
 .PHONY: clean
 clean:
-	rm -f *.bin *.def IWCONFIG
+	rm -f $(BINS) $(TMPS) $(foreach t,$(BINS),build/$(t))
+
+.PHONY: distclean
+distclean:
+	rm -rf build/*
diff --git a/software/ugophy/.gitignore b/software/ugophy/.gitignore
index b216dab..7cef27e 100644
--- a/software/ugophy/.gitignore
+++ b/software/ugophy/.gitignore
@@ -2,7 +2,4 @@
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-*.tap
-player.bin
-ugoph.bin
-.vscode
+build
diff --git a/software/ugophy/Makefile b/software/ugophy/Makefile
index cdf74da..5e2c601 100644
--- a/software/ugophy/Makefile
+++ b/software/ugophy/Makefile
@@ -1,15 +1,83 @@
 # SPDX-FileCopyrightText: Copyright (C) 2019 Alexander Sharikhin
 #
+# SPDX-FileContributor: 2021 Ivan Tatarinov <ivan-tat@ya.ru>
+#
 # SPDX-License-Identifier: GPL-3.0-or-later
+#
+# Supported environments:
+#   * GNU on Linux, FreeBSD etc.
+#   * GNU on Windows NT (using MinGW/MSYS/Cygwin/WSL)
+#
+# Build:
+#   make [<TARGET> ...]
+# Install / Uninstall:
+#   make [prefix=<PREFIX>] install | uninstall
+# Clean:
+#   make clean | distclean
+#
+# where:
+#   <TARGET> is one of values for `BINS' variable prefixed with "build/"
+#     (see target `all' below).
+#   <PREFIX> is a prefix directory to install files into.
 
 include ../../sdk/common.mk
 
-.PHONY: all
-all: ugoph.bin
+# Use uppercase for FAT filesystem
+srcdir		= .
+prefix		?= .
+exec_prefix	?= $(prefix)
+bindir		?= $(exec_prefix)/BIN
 
-ugoph.bin ugoph.tap: main.asm tscreen.asm keyboard.asm utils.asm wifi.asm gopher.asm render.asm textrender.asm uart.asm ring.asm esxdos.asm vtpl.asm
-	sjasmplus $<
+# Disable execution mode for FAT filesystem
+INSTALL		?= install
+INSTALL_PROGRAM	?= $(INSTALL) -m 644
+RM		= rm -f
+
+AS		= sjasmplus
+ifeq ($(USE_SJASMPLUS_VERSION),sjasmplus)
+AFLAGS		= --nobanner
+else ifeq ($(USE_SJASMPLUS_VERSION),z00m128)
+AFLAGS		= --nologo
+else
+AFLAGS		=
+endif
+
+BINS=\
+ UGOPH
+
+.PHONY: all
+all: $(foreach t,$(BINS),build/$(t))
+
+build\
+$(DESTDIR)$(bindir):
+	mkdir -p $@
+
+build/UGOPH: $(srcdir)/main.asm\
+ $(srcdir)/tscreen.asm\
+ $(srcdir)/keyboard.asm\
+ $(srcdir)/utils.asm\
+ $(srcdir)/wifi.asm\
+ $(srcdir)/gopher.asm\
+ $(srcdir)/render.asm\
+ $(srcdir)/textrender.asm\
+ $(srcdir)/uart.asm\
+ $(srcdir)/ring.asm\
+ $(srcdir)/esxdos.asm\
+ $(srcdir)/vtpl.asm\
+ | build
+	$(AS) $(AFLAGS) --raw=$@ $<
+
+.PHONY: install
+install: $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
+
+.PHONY: uninstall
+uninstall:
+	$(RM) $(foreach t,$(BINS),$(DESTDIR)$(bindir)/$(t))
 
 .PHONY: clean
 clean:
-	rm -f ugoph.bin ugoph.tap
+	rm -f $(foreach t,$(BINS),build/$(t))
+
+.PHONY: distclean
+distclean:
+	rm -rf build/*
diff --git a/software/ugophy/main.asm b/software/ugophy/main.asm
index 4ff208e..f5b2b79 100644
--- a/software/ugophy/main.asm
+++ b/software/ugophy/main.asm
@@ -92,5 +92,5 @@ player
     DISPLAY "Player ends: ", $
     ENT
 eop equ $
-    SAVEBIN "ugoph.bin", Start, $ - Start
-    SAVETAP "ugoph.tap", Start
+;   SAVEBIN "ugoph.bin", Start, $ - Start
+;   SAVETAP "ugoph.tap", Start