diff --git a/selfhost/cmd/w6l/main.combined.ww b/selfhost/cmd/w6l/main.combined.ww
index 7ba25de5..10dbffa5 100644
--- a/selfhost/cmd/w6l/main.combined.ww
+++ b/selfhost/cmd/w6l/main.combined.ww
@@ -812,115 +812,6 @@ package rt;
 // a future task (task #39). ref/hare/rt/malloc.ha:27.
 @symbol("rt_malloc") export fn malloc(n: u64) *void;
 
-// selfhost/cmd/w6l/sym.ww — port of cmd/w6l/sym.c.
-//
-// Linker symbol table. Singly-linked list, usually a few hundred
-// entries; hashing isn't worth it yet.
-
-package w6l;
-
-type lsym = struct {
-	name:        str,
-	val:         u64,	// offset within combined .text (or .data when
-				// indata=1) once linked
-	defined:     i32,	// 1 if some lobj defines this symbol
-	indata:      i32,	// 1 if defined in .data (writable globals)
-	owner:       *lobj,
-	idxinowner:  i32,
-	// Dynamic-linking fields. Set by resolve when an undefined sym
-	// is provided by some loaded lso. pltidx and dynsymidx default
-	// to -1 (set explicitly by resolve; alloc-zeroing gives 0, not -1).
-	isdyn:       i32,
-	dynlib:      *lso,
-	dynversion:  str,	// matched export's version; len 0 if none
-	pltidx:      i32,
-	dynsymidx:   i32,
-	snext:       *lsym,
-};
-
-type lrel = struct {
-	off:    u64,	// offset within the relocation's section
-	section: i32,	// 0 = .text, 1 = .data
-	kind:   i32,	// R_X86_64_*
-	sym:    *lsym,
-	addend: i64,
-	rnext:  *lrel,
-};
-
-type lobj = struct {
-	path:     str,
-	buf:      *u8,	// object bytes
-	len:      u64,
-	textoff:  u64,	// offset of .text in combined output
-	textsize: u64,
-	dataoff:  u64,	// offset of .data in combined output
-	datasize: u64,	// bytes contributed to combined .data (0 if none)
-	onext:    *lobj,
-};
-
-// lexport — one entry per GLOBAL/WEAK symbol exported by a loaded .so.
-// Stored as a chain in the order the .so's dynsym presents them, so
-// soprovides_v's first-match semantics agree with the C version.
-type lexport = struct {
-	name:    str,
-	version: str,	// len 0 for unversioned globals
-	enext:   *lexport,
-};
-
-type lso = struct {
-	path:    str,	// full filesystem path used to load
-	soname:  str,	// DT_SONAME, or basename if missing
-	exports: *lexport,	// dynsym-order chain of exported names
-	sonext:  *lso,
-};
-
-type lnk = struct {
-	objs:    *lobj,
-	sos:     *lso,
-	syms:    *lsym,
-	rels:    *lrel,
-	text:    *u8,	// combined .text
-	textcap: u64,
-	textlen: u64,
-	// Combined .data (writable). Empty unless any input .o has a
-	// .data PROGBITS section.
-	data:    *u8,
-	datacap: u64,
-	datalen: u64,
-	errs:    i32,
-	dynn:    i32,	// number of syms routed through PLT
-};
-
-fn streq(a: str, b: str) bool = {
-	if (a.len != b.len) { return false; };
-	let i: i32 = 0;
-	for (i < a.len) {
-		if (a[i] != b[i]) { return false; };
-		i += 1;
-	};
-	return true;
-};
-
-export fn intern(l: *lnk, name: str) *lsym = {
-	let s: *lsym = l.syms;
-	for (s != nil) {
-		if (streq(s.name, name)) { return s; };
-		s = s.snext;
-	};
-	let n: *lsym = alloc(lsym { name = name, snext = l.syms })!;
-	l.syms = n;
-	return n;
-};
-
-export fn lookup(l: *lnk, name: str) *lsym = {
-	let s: *lsym = l.syms;
-	for (s != nil) {
-		if (streq(s.name, name)) { return s; };
-		s = s.snext;
-	};
-	return nil;
-};
-
 // types — integer limits. Mirrors Hare's types::limits (I8_MAX, …)
 // platform-fixed for amd64. Numeric helpers live in lib/math, matching
 // Hare's split between types::limits and math::.
@@ -2941,6 +2832,115 @@ export fn rpad(s: str, p: rune, maxlen: i32) str = {
 	return frombytes(buf);
 };
 
+// selfhost/cmd/w6l/sym.ww — port of cmd/w6l/sym.c.
+//
+// Linker symbol table. Singly-linked list, usually a few hundred
+// entries; hashing isn't worth it yet.
+
+package w6l;
+
+type lsym = struct {
+	name:        str,
+	val:         u64,	// offset within combined .text (or .data when
+				// indata=1) once linked
+	defined:     i32,	// 1 if some lobj defines this symbol
+	indata:      i32,	// 1 if defined in .data (writable globals)
+	owner:       *lobj,
+	idxinowner:  i32,
+	// Dynamic-linking fields. Set by resolve when an undefined sym
+	// is provided by some loaded lso. pltidx and dynsymidx default
+	// to -1 (set explicitly by resolve; alloc-zeroing gives 0, not -1).
+	isdyn:       i32,
+	dynlib:      *lso,
+	dynversion:  str,	// matched export's version; len 0 if none
+	pltidx:      i32,
+	dynsymidx:   i32,
+	snext:       *lsym,
+};
+
+type lrel = struct {
+	off:    u64,	// offset within the relocation's section
+	section: i32,	// 0 = .text, 1 = .data
+	kind:   i32,	// R_X86_64_*
+	sym:    *lsym,
+	addend: i64,
+	rnext:  *lrel,
+};
+
+type lobj = struct {
+	path:     str,
+	buf:      *u8,	// object bytes
+	len:      u64,
+	textoff:  u64,	// offset of .text in combined output
+	textsize: u64,
+	dataoff:  u64,	// offset of .data in combined output
+	datasize: u64,	// bytes contributed to combined .data (0 if none)
+	onext:    *lobj,
+};
+
+// lexport — one entry per GLOBAL/WEAK symbol exported by a loaded .so.
+// Stored as a chain in the order the .so's dynsym presents them, so
+// soprovides_v's first-match semantics agree with the C version.
+type lexport = struct {
+	name:    str,
+	version: str,	// len 0 for unversioned globals
+	enext:   *lexport,
+};
+
+type lso = struct {
+	path:    str,	// full filesystem path used to load
+	soname:  str,	// DT_SONAME, or basename if missing
+	exports: *lexport,	// dynsym-order chain of exported names
+	sonext:  *lso,
+};
+
+type lnk = struct {
+	objs:    *lobj,
+	sos:     *lso,
+	syms:    *lsym,
+	rels:    *lrel,
+	text:    *u8,	// combined .text
+	textcap: u64,
+	textlen: u64,
+	// Combined .data (writable). Empty unless any input .o has a
+	// .data PROGBITS section.
+	data:    *u8,
+	datacap: u64,
+	datalen: u64,
+	errs:    i32,
+	dynn:    i32,	// number of syms routed through PLT
+};
+
+fn streq(a: str, b: str) bool = {
+	if (a.len != b.len) { return false; };
+	let i: i32 = 0;
+	for (i < a.len) {
+		if (a[i] != b[i]) { return false; };
+		i += 1;
+	};
+	return true;
+};
+
+export fn intern(l: *lnk, name: str) *lsym = {
+	let s: *lsym = l.syms;
+	for (s != nil) {
+		if (streq(s.name, name)) { return s; };
+		s = s.snext;
+	};
+	let n: *lsym = alloc(lsym { name = name, snext = l.syms })!;
+	l.syms = n;
+	return n;
+};
+
+export fn lookup(l: *lnk, name: str) *lsym = {
+	let s: *lsym = l.syms;
+	for (s != nil) {
+		if (streq(s.name, name)) { return s; };
+		s = s.snext;
+	};
+	return nil;
+};
+
 // selfhost/cmd/w6l/obj.ww — port of cmd/w6l/obj.c.
 //
 // Loads relocatable ELF64 .o files emitted by w6a, appends .text to
@@ -5050,6 +5050,7 @@ package main;
 
 import os;
 import rt;
+import strings;
 import sym;
 import obj;
 import dyn;
@@ -5146,23 +5147,12 @@ fn islinkable(path: *u8) bool = {
 	let n: i64 = os.read(fd, &mp[0], 8u64);
 	os.close(fd);
 	if (n < 4i64) { return false; };
-	// archive: "!<arch>\n"
-	if (n >= 8i64) {
-		if (mp[0u64] == '!') { if (mp[1u64] == '<') {
-		if (mp[2u64] == 'a') { if (mp[3u64] == 'r') {
-		if (mp[4u64] == 'c') { if (mp[5u64] == 'h') {
-		if (mp[6u64] == '>') { if (mp[7u64] == '\n') {
-			return true;
-		}; }; }; }; }; }; }; };
-	};
-	// ELF: "\x7fELF"
-	if (mp[0u64] == 127u8) {
-		if (mp[1u64] == 'E') {
-			if (mp[2u64] == 'L') {
-				if (mp[3u64] == 'F') { return true; };
-			};
-		};
-	};
+	// hasprefix length-bails when the header is shorter than the magic,
+	// matching the old n>=8 archive guard (str len < 8 => no match).
+	let hn: i32 = n: i32;
+	let hdr: str = strings.frombytes(mp[0:hn]);
+	if (strings.hasprefix(hdr, "!<arch>\n")) { return true; };
+	if (strings.hasprefix(hdr, "\x7fELF")) { return true; };
 	return false;
 };
 
@@ -5216,10 +5206,8 @@ fn isso(path: *u8) i32 = {
 	let n: i64 = os.read(fd, &mp[0], 20u64);
 	os.close(fd);
 	if (n < 20i64) { return 0; };
-	if (mp[0u64] != 127u8) { return 0; };
-	if (mp[1u64] != 'E') { return 0; };
-	if (mp[2u64] != 'L') { return 0; };
-	if (mp[3u64] != 'F') { return 0; };
+	let hdr: str = strings.frombytes(mp[0:4]);
+	if (!strings.hasprefix(hdr, "\x7fELF")) { return 0; };
 	// e_type at offset 16, u16 little-endian
 	let t: u16 = (mp[16u64]: u16) | ((mp[17u64]: u16) << 8u16);
 	if (t == 3u16) { return 1; };
diff --git a/selfhost/cmd/w6l/main.ww b/selfhost/cmd/w6l/main.ww
index f74d021a..00320423 100644
--- a/selfhost/cmd/w6l/main.ww
+++ b/selfhost/cmd/w6l/main.ww
@@ -10,6 +10,7 @@ package main;
 
 import os;
 import rt;
+import strings;
 import sym;
 import obj;
 import dyn;
@@ -106,23 +107,12 @@ fn islinkable(path: *u8) bool = {
 	let n: i64 = os.read(fd, &mp[0], 8u64);
 	os.close(fd);
 	if (n < 4i64) { return false; };
-	// archive: "!<arch>\n"
-	if (n >= 8i64) {
-		if (mp[0u64] == '!') { if (mp[1u64] == '<') {
-		if (mp[2u64] == 'a') { if (mp[3u64] == 'r') {
-		if (mp[4u64] == 'c') { if (mp[5u64] == 'h') {
-		if (mp[6u64] == '>') { if (mp[7u64] == '\n') {
-			return true;
-		}; }; }; }; }; }; }; };
-	};
-	// ELF: "\x7fELF"
-	if (mp[0u64] == 127u8) {
-		if (mp[1u64] == 'E') {
-			if (mp[2u64] == 'L') {
-				if (mp[3u64] == 'F') { return true; };
-			};
-		};
-	};
+	// hasprefix length-bails when the header is shorter than the magic,
+	// matching the old n>=8 archive guard (str len < 8 => no match).
+	let hn: i32 = n: i32;
+	let hdr: str = strings.frombytes(mp[0:hn]);
+	if (strings.hasprefix(hdr, "!<arch>\n")) { return true; };
+	if (strings.hasprefix(hdr, "\x7fELF")) { return true; };
 	return false;
 };
 
@@ -176,10 +166,8 @@ fn isso(path: *u8) i32 = {
 	let n: i64 = os.read(fd, &mp[0], 20u64);
 	os.close(fd);
 	if (n < 20i64) { return 0; };
-	if (mp[0u64] != 127u8) { return 0; };
-	if (mp[1u64] != 'E') { return 0; };
-	if (mp[2u64] != 'L') { return 0; };
-	if (mp[3u64] != 'F') { return 0; };
+	let hdr: str = strings.frombytes(mp[0:4]);
+	if (!strings.hasprefix(hdr, "\x7fELF")) { return 0; };
 	// e_type at offset 16, u16 little-endian
 	let t: u16 = (mp[16u64]: u16) | ((mp[17u64]: u16) << 8u16);
 	if (t == 3u16) { return 1; };