diff --git a/ports/nasm/build.sh b/ports/nasm/build.sh
new file mode 100755
index 00000000..bdeeec03
--- /dev/null
+++ b/ports/nasm/build.sh
@@ -0,0 +1,8 @@
+#!/bin/bash ../install.sh
+
+NAME='nasm'
+VERSION='2.16.03'
+DOWNLOAD_URL="https://www.nasm.us/pub/nasm/releasebuilds/$VERSION/nasm-$VERSION.tar.gz#5bc940dd8a4245686976a8f7e96ba9340a0915f2d5b88356874890e207bdb581"
+CONFIGURE_OPTIONS=(
+	'--disable-gdb'
+)
diff --git a/ports/nasm/patches/0001-add-banan_os-target.patch b/ports/nasm/patches/0001-add-banan_os-target.patch
new file mode 100644
index 00000000..95999285
--- /dev/null
+++ b/ports/nasm/patches/0001-add-banan_os-target.patch
@@ -0,0 +1,12 @@
+diff -ruN nasm-2.16.03/autoconf/helpers/config.sub nasm-2.16.03-banan_os/autoconf/helpers/config.sub
+--- nasm-2.16.03/autoconf/helpers/config.sub	2024-04-17 20:04:08.000000000 +0300
++++ nasm-2.16.03-banan_os/autoconf/helpers/config.sub	2024-08-18 18:47:13.768447183 +0300
+@@ -1754,7 +1754,7 @@
+ 	     | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
+ 	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
+ 	     | nsk* | powerunix* | genode* | zvmoe* | qnx* | emx* | zephyr* \
+-	     | fiwix* )
++	     | fiwix* | banan_os* )
+ 		;;
+ 	# This one is extra strict with allowed versions
+ 	sco3.2v2 | sco3.2v[4-9]* | sco5v6*)
diff --git a/ports/nasm/patches/0002-do-not-pass-t-to-fopen.patch b/ports/nasm/patches/0002-do-not-pass-t-to-fopen.patch
new file mode 100644
index 00000000..d55ac460
--- /dev/null
+++ b/ports/nasm/patches/0002-do-not-pass-t-to-fopen.patch
@@ -0,0 +1,50 @@
+diff -ruN nasm-2.16.03/nasmlib/file.c nasm-2.16.03-banan_os/nasmlib/file.c
+--- nasm-2.16.03/nasmlib/file.c	2024-04-17 20:04:08.000000000 +0300
++++ nasm-2.16.03-banan_os/nasmlib/file.c	2025-01-25 23:07:51.415526537 +0200
+@@ -160,30 +160,7 @@
+ 
+     osfname = os_mangle_filename(filename);
+     if (osfname) {
+-        os_fopenflag fopen_flags[4];
+-        memset(fopen_flags, 0, sizeof fopen_flags);
+-
+-        fopen_flags[0] = 'r';
+-        fopen_flags[1] = (flags & NF_TEXT) ? 't' : 'b';
+-
+-#if defined(__GLIBC__) || defined(__linux__)
+-        /*
+-         * Try to open this file with memory mapping for speed, unless we are
+-         * going to do it "manually" with nasm_map_file()
+-         */
+-        if (!(flags & NF_FORMAP))
+-            fopen_flags[2] = 'm';
+-#endif
+-
+-        while (true) {
+-            f = os_fopen(osfname, fopen_flags);
+-            if (f || errno != EINVAL || !fopen_flags[2])
+-                break;
+-
+-            /* We got EINVAL but with 'm'; try again without 'm' */
+-            fopen_flags[2] = '\0';
+-        }
+-
++		f = os_fopen(osfname, "r");
+         os_free_filename(osfname);
+     }
+ 
+@@ -201,13 +178,7 @@
+ 
+     osfname = os_mangle_filename(filename);
+     if (osfname) {
+-        os_fopenflag fopen_flags[3];
+-
+-        fopen_flags[0] = 'w';
+-        fopen_flags[1] = (flags & NF_TEXT) ? 't' : 'b';
+-        fopen_flags[2] = '\0';
+-
+-        f = os_fopen(osfname, fopen_flags);
++        f = os_fopen(osfname, "w");
+         os_free_filename(osfname);
+     }
+