diff --git a/atrcopy/dos33.py b/atrcopy/dos33.py
index dcdf21b..96b1010 100644
--- a/atrcopy/dos33.py
+++ b/atrcopy/dos33.py
@@ -251,7 +251,7 @@ class Dos33Dirent(Dirent):
         values[1] = self.sector
         values[2] = self.flag
         n = min(len(self.filename), 30)
-        data[3:3+n] = np.fromstring(self.filename.encode("ascii"), dtype=np.uint8) | 0x80
+        data[3:3+n] = np.frombuffer(self.filename.encode("ascii"), dtype=np.uint8) | 0x80
         data[3+n:] = ord(' ') | 0x80
         if self.deleted:
             data[0x20] = self.track
diff --git a/atrcopy/kboot.py b/atrcopy/kboot.py
index 0728bb5..010d74a 100644
--- a/atrcopy/kboot.py
+++ b/atrcopy/kboot.py
@@ -86,7 +86,7 @@ xexboot_header = b'\x00\x03\x00\x07\r\x07L\r\x07\x1c[\x00\x00\xa0\x00\x8c\t\x03\
 
 
 def insert_bytes(data, offset, string, color):
-    s = np.fromstring(string.upper(), dtype=np.uint8) - 32  # convert to internal
+    s = np.frombuffer(string.upper(), dtype=np.uint8) - 32  # convert to internal
     s = s | color
     count = len(s)
     tx = offset + (20 - count) // 2
@@ -103,7 +103,7 @@ def add_xexboot_header(bytes, bootcode=None, title=b"DEMO", author=b"an atari us
     paragraphs = padded_size // 16
 
     if bootcode is None:
-        bootcode = np.fromstring(xexboot_header, dtype=np.uint8)
+        bootcode = np.copy(np.frombuffer(xexboot_header, dtype=np.uint8))
     else:
         # don't insert title or author in user supplied bootcode; would have to
         # assume that the user supplied everything desired in their own code!
diff --git a/atrcopy/mame.py b/atrcopy/mame.py
index 370849a..20850f1 100644
--- a/atrcopy/mame.py
+++ b/atrcopy/mame.py
@@ -46,7 +46,7 @@ class MameZipImage(DiskImageBase):
         segment_info = []
         offset = 0
         for item in zf.infolist():
-            rom = np.fromstring(zf.open(item).read(), dtype=np.uint8)
+            rom = np.frombuffer(zf.open(item).read(), dtype=np.uint8)
             roms.append(rom)
             segment_info.append((offset, item.file_size, item.filename, item.CRC))
             offset += item.file_size
diff --git a/atrcopy/standard_delivery.py b/atrcopy/standard_delivery.py
index fe2a2f1..ccd8622 100644
--- a/atrcopy/standard_delivery.py
+++ b/atrcopy/standard_delivery.py
@@ -165,7 +165,7 @@ from . fstbt import fstbt
 
 def get_fstbt_code(data, address_list, run_addr):
     pointer = len(fstbt)
-    data[0:pointer] = np.fromstring(fstbt, dtype=np.uint8)
+    data[0:pointer] = np.frombuffer(fstbt, dtype=np.uint8)
     hi, lo = divmod(run_addr, 256)
     data[pointer:pointer + 2] = (lo, hi)
     address_list.append(0xc0)  # last sector flag
diff --git a/atrcopy/utils.py b/atrcopy/utils.py
index ad022e9..3bf1790 100644
--- a/atrcopy/utils.py
+++ b/atrcopy/utils.py
@@ -29,7 +29,7 @@ def to_numpy(value):
     if type(value) is np.ndarray:
         return value
     elif type(value) is bytes:
-        return np.fromstring(value, dtype=np.uint8)
+        return np.copy(np.frombuffer(value, dtype=np.uint8))
     elif type(value) is list:
     	return np.asarray(value, dtype=np.uint8)
     raise TypeError("Can't convert to numpy data")
diff --git a/test/test_add_file.py b/test/test_add_file.py
index afee838..eca940d 100644
--- a/test/test_add_file.py
+++ b/test/test_add_file.py
@@ -25,7 +25,7 @@ class BaseFilesystemModifyTest:
             filename = "%s%d.BIN" % (prefix, count)
             self.image.write_file(filename, None, data)
             assert len(self.image.files) == orig_num_files + count
-            data2 = np.fromstring(self.image.find_file(filename), dtype=np.uint8)
+            data2 = np.frombuffer(self.image.find_file(filename), dtype=np.uint8)
             assert np.array_equal(data, data2[0:len(data)])
             count += 1
 
@@ -33,7 +33,7 @@ class BaseFilesystemModifyTest:
         count = 1
         for data in entries:
             filename = "%s%d.BIN" % (prefix, count)
-            data2 = np.fromstring(self.image.find_file(filename), dtype=np.uint8)
+            data2 = np.frombuffer(self.image.find_file(filename), dtype=np.uint8)
             assert np.array_equal(data, data2[0:len(data)])
             count += 1
             filenames.append(filename)
@@ -50,7 +50,7 @@ class BaseFilesystemModifyTest:
         self.image.write_file("TEST.XEX", None, data)
         assert len(self.image.files) == self.num_files_in_sample + 1
 
-        data2 = np.fromstring(self.image.find_file("TEST.XEX"), dtype=np.uint8)
+        data2 = np.frombuffer(self.image.find_file("TEST.XEX"), dtype=np.uint8)
         assert np.array_equal(data, data2[0:len(data)])
 
     def test_50k(self):