diff --git a/amitools/binfmt/elf/ELFDumper.py b/amitools/binfmt/elf/ELFDumper.py
index 77a7e6d5..0df806d6 100644
--- a/amitools/binfmt/elf/ELFDumper.py
+++ b/amitools/binfmt/elf/ELFDumper.py
@@ -32,7 +32,6 @@ def dump_sections(self, show_relocs=False, show_debug=False):
         print("ELF Sections")
         print("id  name             size      rela  syms  type       flags")
         for sect in self.elf.sections:
-
             # determine number of relocations
             rela = sect.get_rela()
             num_rela = len(rela)
diff --git a/amitools/fs/ADFSBitmap.py b/amitools/fs/ADFSBitmap.py
index 4e91e13e..c22b8159 100644
--- a/amitools/fs/ADFSBitmap.py
+++ b/amitools/fs/ADFSBitmap.py
@@ -315,7 +315,7 @@ def print_free(self, brief=False):
         res = self.blkdev.reserved
         for i in range(self.blkdev.num_blocks):
             if i >= res and self.get_bit(i):
-                bm[i] = "F"
+                bm[i] = ord("F")
         self.print_draw_bitmap(bm, brief)
 
     def print_used(self, brief=False):
@@ -323,39 +323,39 @@ def print_used(self, brief=False):
         res = self.blkdev.reserved
         for i in range(self.blkdev.num_blocks):
             if i >= res and not self.get_bit(i):
-                bm[i] = "#"
+                bm[i] = ord("#")
         self.print_draw_bitmap(bm, brief)
 
     def draw_on_bitmap(self, bm):
         # show reserved blocks
         res = self.blkdev.reserved
-        bm[0:res] = "x" * res
+        bm[0:res] = b"x" * res
         # root block
-        bm[self.root_blk.blk_num] = "R"
+        bm[self.root_blk.blk_num] = ord("R")
         # bitmap blocks
         for bm_blk in self.bitmap_blks:
-            bm[bm_blk.blk_num] = "b"
+            bm[bm_blk.blk_num] = ord("b")
         # bitmap ext blocks
         for ext_blk in self.ext_blks:
-            bm[ext_blk.blk_num] = "B"
+            bm[ext_blk.blk_num] = ord("B")
 
     def print_draw_bitmap(self, bm, brief=False):
-        line = ""
+        line = bytearray()
         blk = 0
         blk_cyl = self.blkdev.sectors * self.blkdev.heads
         found = False
         for i in range(self.blkdev.num_blocks):
             c = bm[i]
-            if ord(c) == 0:
-                c = "."
+            if c == 0:
+                c = ord(".")
             else:
                 found = True
-            line += c
+            line.append(c)
             if i % self.blkdev.sectors == self.blkdev.sectors - 1:
-                line += " "
+                line.append(ord(" "))
             if i % blk_cyl == blk_cyl - 1:
                 if not brief or found:
-                    print("%8d: %s" % (blk, line))
+                    print("%8d: %s" % (blk, line.decode("utf-8")))
                 blk += blk_cyl
-                line = ""
+                line = bytearray()
                 found = False
diff --git a/amitools/fs/ADFSDir.py b/amitools/fs/ADFSDir.py
index c964a02a..e20b88fa 100644
--- a/amitools/fs/ADFSDir.py
+++ b/amitools/fs/ADFSDir.py
@@ -374,14 +374,14 @@ def get_path(self, pc, allow_file=True, allow_dir=True):
 
     def draw_on_bitmap(self, bm, show_all=False, first=True):
         blk_num = self.block.blk_num
-        bm[blk_num] = "D"
+        bm[blk_num] = ord("D")
         if show_all or first:
             self.ensure_entries()
             for e in self.entries:
                 e.draw_on_bitmap(bm, show_all, False)
         if self.dcache_blks != None:
             for dcb in self.dcache_blks:
-                bm[dcb.blk_num] = "C"
+                bm[dcb.blk_num] = ord("C")
 
     def get_block_nums(self):
         self.ensure_entries()
diff --git a/amitools/fs/ADFSFile.py b/amitools/fs/ADFSFile.py
index 803236db..8b58bc9d 100644
--- a/amitools/fs/ADFSFile.py
+++ b/amitools/fs/ADFSFile.py
@@ -275,11 +275,11 @@ def write(self):
             left -= bs
 
     def draw_on_bitmap(self, bm, show_all=False, first=False):
-        bm[self.block.blk_num] = "H"
+        bm[self.block.blk_num] = ord("H")
         for b in self.ext_blk_nums:
-            bm[b] = "E"
+            bm[b] = ord("E")
         for b in self.data_blk_nums:
-            bm[b] = "d"
+            bm[b] = ord("d")
 
     def get_block_nums(self):
         result = [self.block.blk_num]
diff --git a/amitools/fs/ADFSVolDir.py b/amitools/fs/ADFSVolDir.py
index ce74bb5d..460e70ae 100644
--- a/amitools/fs/ADFSVolDir.py
+++ b/amitools/fs/ADFSVolDir.py
@@ -18,7 +18,7 @@ def __repr__(self):
 
     def draw_on_bitmap(self, bm, show_all=False, first=True):
         blk_num = self.block.blk_num
-        bm[blk_num] = "V"
+        bm[blk_num] = ord("V")
         if show_all or first:
             self.ensure_entries()
             for e in self.entries:
diff --git a/amitools/fs/Imager.py b/amitools/fs/Imager.py
index ff95fa95..086a2a8c 100644
--- a/amitools/fs/Imager.py
+++ b/amitools/fs/Imager.py
@@ -17,7 +17,6 @@
 
 
 class Imager:
-
     META_MODE_NONE = 0
     META_MODE_DB = 1
     META_MODE_FSUAE = 2
diff --git a/amitools/fs/blkdev/ADFBlockDevice.py b/amitools/fs/blkdev/ADFBlockDevice.py
index 79c54007..661d0286 100644
--- a/amitools/fs/blkdev/ADFBlockDevice.py
+++ b/amitools/fs/blkdev/ADFBlockDevice.py
@@ -2,7 +2,6 @@
 
 
 class ADFBlockDevice(BlockDevice):
-
     # number of total sectors for DD/HD disks
     DD_SECS = 80 * 2 * 11
     HD_SECS = 80 * 2 * 22
diff --git a/amitools/fs/block/Block.py b/amitools/fs/block/Block.py
index 9e146297..391af05d 100644
--- a/amitools/fs/block/Block.py
+++ b/amitools/fs/block/Block.py
@@ -62,6 +62,9 @@ def is_file_data_block(self):
     def is_comment_block(self):
         return self.type == Block.T_COMMENT
 
+    def is_dir_cache_block(self):
+        return self.type == Block.T_DIR_CACHE
+
     def read(self):
         if self.data == None:
             self._read_data()
diff --git a/amitools/fs/block/BlockFactory.py b/amitools/fs/block/BlockFactory.py
new file mode 100644
index 00000000..1f9c28c3
--- /dev/null
+++ b/amitools/fs/block/BlockFactory.py
@@ -0,0 +1,33 @@
+from .Block import Block
+from .RootBlock import RootBlock
+from .UserDirBlock import UserDirBlock
+from .FileHeaderBlock import FileHeaderBlock
+from .FileListBlock import FileListBlock
+from .FileDataBlock import FileDataBlock
+from .CommentBlock import CommentBlock
+from .DirCacheBlock import DirCacheBlock
+
+
+class BlockFactory:
+    @classmethod
+    def create_block(cls, blkdev, blk_num, type, sub_type):
+        if type == Block.T_SHORT:
+            if sub_type == Block.ST_ROOT:
+                return RootBlock(blkdev, blk_num)
+            elif sub_type == Block.ST_USERDIR:
+                return UserDirBlock(blkdev, blk_num)
+            elif sub_type == Block.ST_FILE:
+                return FileHeaderBlock(blkdev, blk_num)
+        elif type == Block.T_LIST:
+            if sub_type == Block.ST_FILE:
+                return FileListBlock(blkdev, blk_num)
+        elif type == Block.T_DATA:
+            return FileDataBlock(blkdev, blk_num)
+        elif type == Block.T_COMMENT:
+            return CommentBlock(blkdev, blk_num)
+        elif type == Block.T_DIR_CACHE:
+            return DirCacheBlock(blkdev, blk_num)
+
+    @classmethod
+    def create_specific_block(cls, block):
+        return cls.create_block(block.blkdev, block.blk_num, block.type, block.sub_type)
diff --git a/amitools/fs/block/UserDirBlock.py b/amitools/fs/block/UserDirBlock.py
index 21d841a8..d18efbd0 100644
--- a/amitools/fs/block/UserDirBlock.py
+++ b/amitools/fs/block/UserDirBlock.py
@@ -6,7 +6,7 @@
 
 
 class UserDirBlock(EntryBlock):
-    def __init__(self, blkdev, blk_num, is_longname):
+    def __init__(self, blkdev, blk_num, is_longname=False):
         EntryBlock.__init__(
             self,
             blkdev,
diff --git a/amitools/rom/rompatcher.py b/amitools/rom/rompatcher.py
index 466f7257..4f2b5742 100644
--- a/amitools/rom/rompatcher.py
+++ b/amitools/rom/rompatcher.py
@@ -137,7 +137,6 @@ def apply_patch(self, access, args):
 
 
 class RomPatcher:
-
     # list of all available patch classes
     patches = [OneMegRomPatch(), FourMegRomPatch(), BootConRomPatch()]
 
diff --git a/amitools/tools/rdbtool.py b/amitools/tools/rdbtool.py
index c777266a..c6323565 100755
--- a/amitools/tools/rdbtool.py
+++ b/amitools/tools/rdbtool.py
@@ -24,6 +24,7 @@
 import amitools.util.ByteSize as ByteSize
 import amitools.util.VerTag as VerTag
 
+
 # ----- commands -----
 class Command:
     def __init__(self, args, opts, edit=False):
diff --git a/amitools/tools/xdftool.py b/amitools/tools/xdftool.py
index 26c2863c..a756571e 100755
--- a/amitools/tools/xdftool.py
+++ b/amitools/tools/xdftool.py
@@ -14,6 +14,8 @@
 from amitools.fs.Repacker import Repacker
 from amitools.fs.block.BootBlock import BootBlock
 from amitools.fs.block.RootBlock import RootBlock
+from amitools.fs.block.Block import Block
+from amitools.fs.block.BlockFactory import BlockFactory
 from amitools.util.CommandQueue import CommandQueue
 from amitools.util.HexDump import *
 import amitools.util.KeyValue as KeyValue
@@ -567,7 +569,7 @@ def handle_vol(self, vol):
         n = len(self.opts)
         if n == 0:
             print(
-                "Usage: block ( boot | root | node <ami_file> [data] | dump <block_no> )"
+                "Usage: block ( boot | root | node <ami_file> [data] | dump <block_no> | decode <block_no> )"
             )
             return 1
         cmd = self.opts[0]
@@ -600,6 +602,24 @@ def handle_vol(self, vol):
                 block_no = int(self.opts[1])
                 data = vol.blkdev.read_block(block_no)
                 print_hex(data)
+        elif cmd == "decode":
+            if n == 1:
+                print("No block number given!")
+                return 1
+            else:
+                block_no = int(self.opts[1])
+                # read block
+                blk = Block(vol.blkdev, block_no)
+                blk.read()
+                if blk.valid:
+                    dec_blk = BlockFactory.create_specific_block(blk)
+                    if dec_blk:
+                        dec_blk.read()
+                        dec_blk.dump()
+                    else:
+                        blk.dump("Unknown")
+                else:
+                    print("Error reading block!")
 
 
 # ----- Bitmap Tools -----
diff --git a/amitools/vamos/astructs/access.py b/amitools/vamos/astructs/access.py
index 6ac56197..c67df06b 100644
--- a/amitools/vamos/astructs/access.py
+++ b/amitools/vamos/astructs/access.py
@@ -3,7 +3,6 @@
 
 
 class AccessStruct(object):
-
     _size_to_width = [None, 0, 1, None, 2]
 
     def __init__(self, mem, struct_def, struct_addr):
diff --git a/amitools/vamos/astructs/astruct.py b/amitools/vamos/astructs/astruct.py
index 10ed8a3e..257564f4 100644
--- a/amitools/vamos/astructs/astruct.py
+++ b/amitools/vamos/astructs/astruct.py
@@ -46,7 +46,6 @@ def get_all_struct_names(self):
 
 
 class FieldDef(FieldDefBase):
-
     _base_offset = 0
     _parent_def = None
 
@@ -322,7 +321,6 @@ def _create_field_type(self, field_def):
 
 
 class AmigaStruct(TypeBase):
-
     # overwrite in derived class!
     _format = None
     # top-level alias names for subfields
diff --git a/amitools/vamos/astructs/astructdef.py b/amitools/vamos/astructs/astructdef.py
index 6f2bac18..8ded8959 100644
--- a/amitools/vamos/astructs/astructdef.py
+++ b/amitools/vamos/astructs/astructdef.py
@@ -39,7 +39,6 @@ def _setup_fields(self, cls, format, type_name):
 
         # run through fields
         for field_type, field_name in format:
-
             # replace self pointers
             if field_type is APTR_SELF:
                 field_type = APTR(cls)
diff --git a/amitools/vamos/lib/dos/MatchFirstNext.py b/amitools/vamos/lib/dos/MatchFirstNext.py
index c316a265..04b4d86f 100644
--- a/amitools/vamos/lib/dos/MatchFirstNext.py
+++ b/amitools/vamos/lib/dos/MatchFirstNext.py
@@ -10,7 +10,6 @@
 
 
 class MatchFirstNext:
-
     DODIR = 4
     DIDDIR = 8
 
diff --git a/amitools/vamos/lib/lexec/SemaphoreManager.py b/amitools/vamos/lib/lexec/SemaphoreManager.py
index 2635bdbd..336ffc04 100644
--- a/amitools/vamos/lib/lexec/SemaphoreManager.py
+++ b/amitools/vamos/lib/lexec/SemaphoreManager.py
@@ -4,7 +4,6 @@
 
 
 class SemaphoreManager:
-
     NT_SIGNALSEM = 15
 
     def __init__(self, alloc, mem):
diff --git a/amitools/vamos/libcore/profile.py b/amitools/vamos/libcore/profile.py
index 3aa8e253..79ccd2e6 100644
--- a/amitools/vamos/libcore/profile.py
+++ b/amitools/vamos/libcore/profile.py
@@ -241,7 +241,6 @@ def dump(self, name, write=print):
 
 
 class LibProfiler(Profiler):
-
     name = "libs"
 
     def __init__(self, names=None, add_calls=False, add_all=False):
diff --git a/amitools/vamos/libnative/initstruct.py b/amitools/vamos/libnative/initstruct.py
index d145f360..13c15252 100644
--- a/amitools/vamos/libnative/initstruct.py
+++ b/amitools/vamos/libnative/initstruct.py
@@ -82,7 +82,6 @@ def init_struct(self, init_table_ptr, memory_ptr, size):
 
 
 class InitStructBuilder(object):
-
     SIZE_LONG = 0
     SIZE_WORD = 1
     SIZE_BYTE = 2
diff --git a/amitools/vamos/libnative/libfuncs.py b/amitools/vamos/libnative/libfuncs.py
index 9eab7608..c16796a0 100644
--- a/amitools/vamos/libnative/libfuncs.py
+++ b/amitools/vamos/libnative/libfuncs.py
@@ -6,7 +6,6 @@
 
 
 class LibFuncs(object):
-
     LVO_Open = 1
     LVO_Close = 2
     LVO_Expunge = 3
diff --git a/amitools/vamos/libstructs/util.py b/amitools/vamos/libstructs/util.py
index b1836c87..2f55dc2e 100644
--- a/amitools/vamos/libstructs/util.py
+++ b/amitools/vamos/libstructs/util.py
@@ -5,6 +5,7 @@
     ULONG,
 )
 
+
 # TagItem
 @AmigaStructDef
 class TagItemStruct(AmigaStruct):
diff --git a/amitools/vamos/libtypes/library.py b/amitools/vamos/libtypes/library.py
index 49d6119f..22e28bcd 100644
--- a/amitools/vamos/libtypes/library.py
+++ b/amitools/vamos/libtypes/library.py
@@ -40,7 +40,7 @@ def alloc(cls, alloc, tag=None, pos_size=0, neg_size=0, fd=None, **kwargs):
             tag=tag,
             pos_size=pos_size,
             neg_size=neg_size,
-            **kwargs
+            **kwargs,
         )
 
 
diff --git a/amitools/vamos/libtypes/resident.py b/amitools/vamos/libtypes/resident.py
index 7d7c3e0c..e98e888d 100644
--- a/amitools/vamos/libtypes/resident.py
+++ b/amitools/vamos/libtypes/resident.py
@@ -10,7 +10,6 @@
 
 @AmigaClassDef
 class Resident(ResidentStruct):
-
     RTC_MATCHWORD = 0x4AFC
 
     @classmethod
diff --git a/test/tools/romtool.py b/test/tools/romtool.py
index f4e680b5..9fbd6cdb 100644
--- a/test/tools/romtool.py
+++ b/test/tools/romtool.py
@@ -1,5 +1,6 @@
 import pytest
 
+
 # tag a parameter for full testing
 def tag_full(value):
     return pytest.param(value, marks=pytest.mark.full)
diff --git a/test/unit/libnative_initres.py b/test/unit/libnative_initres.py
index 568c5603..d2bf63e2 100644
--- a/test/unit/libnative_initres.py
+++ b/test/unit/libnative_initres.py
@@ -29,6 +29,7 @@ def libnative_initres_init_test(buildlibnix):
     sp = init_addr - 4
     # load lib
     seglist, addr, size, end = load_lib(alloc, buildlibnix)
+
     # setup init func
     def init_func(op, pc):
         assert cpu.r_reg(REG_A0) == seglist.get_baddr()
@@ -63,6 +64,7 @@ def libnative_initres_autoinit_test(buildlibnix):
     sp = init_addr - 4
     # load lib
     seglist, addr, size, end = load_lib(alloc, buildlibnix)
+
     # setup init func
     def init_func(op, pc):
         assert cpu.r_reg(REG_A0) == seglist.get_baddr()