diff --git a/src/devices/file.c b/src/devices/file.c
index 56a1baf..583a54b 100644
--- a/src/devices/file.c
+++ b/src/devices/file.c
@@ -76,26 +76,70 @@ reset(UxnFile *c)
 }
 
 static Uint16
-get_entry(char *p, Uint16 len, const char *pathname, const char *basename, int fail_nonzero)
+stat_fill(Uint16 addr, Uint16 len, char c)
 {
-	struct stat st;
-	if(len < strlen(basename) + 8)
-		return 0;
-	if(stat(pathname, &st))
-		return fail_nonzero ? snprintf(p, len, "!!!! %s\n", basename) : 0;
-	else if(S_ISDIR(st.st_mode))
-		return snprintf(p, len, "---- %s/\n", basename);
-	else if(st.st_size < 0x10000)
-		return snprintf(p, len, "%04x %s\n", (unsigned int)st.st_size, basename);
-	else
-		return snprintf(p, len, "???? %s\n", basename);
+	Uint16 i;
+	for (i = 0; i < len; i++)
+		uxn.ram[(addr + i) & 0xffff] = c;
+	return len;
 }
 
 static Uint16
-file_read_dir(UxnFile *c, char *dest, Uint16 len)
+stat_size(Uint16 addr, Uint16 len, off_t size)
+{
+	Uint16 i;
+	for (i = 1; i <= len; i++) {
+		char c = '0' + (Uint8)(size & 0xf);
+		if (c > '9') c += 39;
+		uxn.ram[(addr + len - i) & 0xffff] = c;
+		size = size >> 4;
+	}
+	if (size > 0)
+		stat_fill(addr, len, '?');
+	return len;
+}
+
+static Uint16
+stat_entry(Uint16 addr, char sym, off_t size, const char *s)
+{
+	Uint16 pos = addr;
+	pos += sym ? stat_fill(pos, 4, sym) : stat_size(pos, 4, size);
+	uxn.ram[(pos++) & 0xffff] = ' ';
+	while(*s)
+		uxn.ram[(pos++) & 0xffff] = *(s++);
+	if (sym == '-')
+		uxn.ram[(pos++) & 0xffff] = '/';
+	uxn.ram[(pos++) & 0xffff] = '\n';
+	return pos - addr;
+}
+
+static Uint16
+get_entry(Uint16 addr, Uint16 len, const char *pathname, const char *basename)
+{
+	struct stat st;
+	int row_size = strlen(basename) + 6; /* 4 bytes, ' ', basename, '\n' */
+	char sym = 0;
+	off_t size = 0;
+
+	if(stat(pathname, &st))
+		sym = '!';
+	else if(S_ISDIR(st.st_mode)) {
+		sym = '-';
+		row_size++; /* directories have a '/' suffix */
+	} else if(st.st_size >= 0x10000)
+		sym = '?';
+	else
+		size = st.st_size;
+
+	return len < row_size ? 0 : stat_entry(addr, sym, size, basename);
+}
+
+static Uint16
+file_read_dir(UxnFile *c, Uint16 addr, Uint16 len)
 {
 	static char pathname[4352];
-	char *p = dest;
+	Uint16 pos = addr;
+	char cwd[PATH_MAX] = {'\0'}, *t;
 	if(c->de == NULL) c->de = readdir(c->dir);
 	for(; c->de != NULL; c->de = readdir(c->dir)) {
 		Uint16 n;
@@ -103,7 +147,6 @@ file_read_dir(UxnFile *c, char *dest, Uint16 len)
 			continue;
 		if(strcmp(c->de->d_name, "..") == 0) {
 			/* hide "sandbox/.." */
-			char cwd[PATH_MAX] = {'\0'}, *t;
 			/* Note there's [currently] no way of chdir()ing from uxn, so $PWD
 			 * is always the sandbox top level. */
 			getcwd(cwd, sizeof(cwd));
@@ -119,12 +162,12 @@ file_read_dir(UxnFile *c, char *dest, Uint16 len)
 			snprintf(pathname, sizeof(pathname), "%s/%s", c->current_filename, c->de->d_name);
 		else
 			pathname[0] = '\0';
-		n = get_entry(p, len, pathname, c->de->d_name, 1);
+		n = get_entry(pos, len, pathname, c->de->d_name);
 		if(!n) break;
-		p += n;
+		pos += n;
 		len -= n;
 	}
-	return p - dest;
+	return pos - addr;
 }
 
 static char *
@@ -176,26 +219,35 @@ file_check_sandbox(UxnFile *c)
 }
 
 static Uint16
-file_init(UxnFile *c, char *filename, size_t max_len, int override_sandbox)
+file_init(UxnFile *c, Uint16 addr)
 {
 	char *p = c->current_filename;
-	size_t len = sizeof(c->current_filename);
+	Uint16 i = addr;
 	reset(c);
-	if(len > max_len) len = max_len;
-	while(len) {
-		if((*p++ = *filename++) == '\0') {
-			if(!override_sandbox) /* override sandbox for loading roms */
-				file_check_sandbox(c);
+	for(;; p++, i++) {
+		if((*p = uxn.ram[i & 0xffff]) == '\0') {
+			file_check_sandbox(c);
 			return 0;
 		}
-		len--;
 	}
-	c->current_filename[0] = '\0';
 	return 0;
 }
 
 static Uint16
-file_read(UxnFile *c, void *dest, int len)
+file_read_file(Uint16 addr, int len, FILE *f)
+{
+	int total = addr + len;
+	if (total <= 0x10000) {
+		return fread(&uxn.ram[addr], 1, len, f);
+	} else {
+		size_t n1 = fread(&uxn.ram[addr], 1, 0x10000 - addr, f);
+		size_t n2 = fread(&uxn.ram[0], 1, total - 0x10000, f);
+		return n1 + n2;
+	}
+}
+
+static Uint16
+file_read(UxnFile *c, Uint16 addr, int len)
 {
 	if(c->outside_sandbox) return 0;
 	if(c->state != FILE_READ && c->state != DIR_READ) {
@@ -206,9 +258,9 @@ file_read(UxnFile *c, void *dest, int len)
 			c->state = FILE_READ;
 	}
 	if(c->state == FILE_READ)
-		return fread(dest, 1, len, c->f);
+		return file_read_file(addr, len, c->f);
 	if(c->state == DIR_READ)
-		return file_read_dir(c, dest, len);
+		return file_read_dir(c, addr, len);
 	return 0;
 }
 
@@ -245,7 +297,22 @@ ensure_parent_dirs(char *p)
 }
 
 static Uint16
-file_write(UxnFile *c, void *src, Uint16 len, Uint8 flags)
+file_write_file(Uint16 addr, int len, FILE *f)
+{
+	int total = addr + len;
+	fflush(stdout);
+	if (total <= 0x10000) {
+		Uint16 n = fwrite(&uxn.ram[addr], 1, len, f);
+		return fflush(f) == 0 ? n : 0;
+	} else {
+		Uint16 n1 = fwrite(&uxn.ram[addr], 1, 0x10000 - addr, f);
+		Uint16 n2 = fwrite(&uxn.ram[0], 1, total - 0x10000, f);
+		return fflush(f) == 0 ? n1 + n2 : 0;
+	}
+}
+
+static Uint16
+file_write(UxnFile *c, Uint16 addr, Uint16 len, Uint8 flags)
 {
 	Uint16 ret = 0;
 	if(c->outside_sandbox) return 0;
@@ -258,8 +325,7 @@ file_write(UxnFile *c, void *src, Uint16 len, Uint8 flags)
 			c->state = FILE_WRITE;
 	}
 	if(c->state == FILE_WRITE) {
-		if((ret = fwrite(src, 1, len, c->f)) > 0 && fflush(c->f) != 0)
-			ret = 0;
+		ret = file_write_file(addr, len, c->f);
 	}
 	if (c->state == DIR_WRITE) {
 		ret = dir_exists(c->current_filename);
@@ -268,38 +334,17 @@ file_write(UxnFile *c, void *src, Uint16 len, Uint8 flags)
 }
 
 static Uint16
-stat_fill(Uint8 *dest, Uint16 len, char c)
-{
-	Uint16 i;
-	for (i = 0; i < len; i++)
-		*(dest++) = c;
-	return len;
-}
-
-static Uint16
-stat_size(Uint8 *dest, Uint16 len, off_t size)
-{
-	Uint16 i;
-	dest += len - 1;
-	for (i = 0; i < len; i++) {
-		*(dest--) = '0' + (Uint8)(size & 0xf);
-		size = size >> 4;
-	}
-	return size == 0 ? len : stat_fill(dest, len, '?');
-}
-
-static Uint16
-file_stat(UxnFile *c, void *dest, Uint16 len)
+file_stat(UxnFile *c, Uint16 addr, Uint16 len)
 {
 	struct stat st;
 	if(c->outside_sandbox)
 		return 0;
 	else if(stat(c->current_filename, &st))
-		return stat_fill(dest, len, '!');
+		return stat_fill(addr, len, '!');
 	else if(S_ISDIR(st.st_mode))
-		return stat_fill(dest, len, '-');
+		return stat_fill(addr, len, '-');
 	else
-		return stat_size(dest, len, st.st_size);
+		return stat_size(addr, len, st.st_size);
 }
 
 static Uint16
@@ -318,9 +363,7 @@ file_deo(Uint8 port)
 	case 0xa5:
 		addr = PEEK2(&uxn.dev[0xa4]);
 		len = PEEK2(&uxn.dev[0xaa]);
-		if(len > 0x10000 - addr)
-			len = 0x10000 - addr;
-		res = file_stat(&uxn_file[0], &uxn.ram[addr], len);
+		res = file_stat(&uxn_file[0], addr, len);
 		POKE2(&uxn.dev[0xa2], res);
 		break;
 	case 0xa6:
@@ -329,32 +372,26 @@ file_deo(Uint8 port)
 		break;
 	case 0xa9:
 		addr = PEEK2(&uxn.dev[0xa8]);
-		res = file_init(&uxn_file[0], (char *)&uxn.ram[addr], 0x10000 - addr, 0);
+		res = file_init(&uxn_file[0], addr);
 		POKE2(&uxn.dev[0xa2], res);
 		break;
 	case 0xad:
 		addr = PEEK2(&uxn.dev[0xac]);
 		len = PEEK2(&uxn.dev[0xaa]);
-		if(len > 0x10000 - addr)
-			len = 0x10000 - addr;
-		res = file_read(&uxn_file[0], &uxn.ram[addr], len);
+		res = file_read(&uxn_file[0], addr, len);
 		POKE2(&uxn.dev[0xa2], res);
 		break;
 	case 0xaf:
 		addr = PEEK2(&uxn.dev[0xae]);
 		len = PEEK2(&uxn.dev[0xaa]);
-		if(len > 0x10000 - addr)
-			len = 0x10000 - addr;
-		res = file_write(&uxn_file[0], &uxn.ram[addr], len, uxn.dev[0xa7]);
+		res = file_write(&uxn_file[0], addr, len, uxn.dev[0xa7]);
 		POKE2(&uxn.dev[0xa2], res);
 		break;
 	/* File 2 */
 	case 0xb5:
 		addr = PEEK2(&uxn.dev[0xb4]);
 		len = PEEK2(&uxn.dev[0xba]);
-		if(len > 0x10000 - addr)
-			len = 0x10000 - addr;
-		res = file_stat(&uxn_file[1], &uxn.ram[addr], len);
+		res = file_stat(&uxn_file[1], addr, len);
 		POKE2(&uxn.dev[0xb2], res);
 		break;
 	case 0xb6:
@@ -363,23 +400,19 @@ file_deo(Uint8 port)
 		break;
 	case 0xb9:
 		addr = PEEK2(&uxn.dev[0xb8]);
-		res = file_init(&uxn_file[1], (char *)&uxn.ram[addr], 0x10000 - addr, 0);
+		res = file_init(&uxn_file[1], addr);
 		POKE2(&uxn.dev[0xb2], res);
 		break;
 	case 0xbd:
 		addr = PEEK2(&uxn.dev[0xbc]);
 		len = PEEK2(&uxn.dev[0xba]);
-		if(len > 0x10000 - addr)
-			len = 0x10000 - addr;
-		res = file_read(&uxn_file[1], &uxn.ram[addr], len);
+		res = file_read(&uxn_file[1], addr, len);
 		POKE2(&uxn.dev[0xb2], res);
 		break;
 	case 0xbf:
 		addr = PEEK2(&uxn.dev[0xbe]);
 		len = PEEK2(&uxn.dev[0xba]);
-		if(len > 0x10000 - addr)
-			len = 0x10000 - addr;
-		res = file_write(&uxn_file[1], &uxn.ram[addr], len, uxn.dev[0xb7]);
+		res = file_write(&uxn_file[1], addr, len, uxn.dev[0xb7]);
 		POKE2(&uxn.dev[0xb2], res);
 		break;
 	}