diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index e696b97..c7bac04 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -4,7 +4,7 @@ on: [push, pull_request]
 
 jobs:
   tox:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
       - name: Install dependencies
         run: |
@@ -15,7 +15,7 @@ jobs:
       - name: Run tox
         run: tox
   test:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
       - name: Install dependencies
         run: |
@@ -27,10 +27,9 @@ jobs:
         # SKIP growpart-lvm test that does not work on github c-i
         run: sudo SKIP=growpart-lvm PATH=$PWD/bin:$PATH ./test/run-all
       - name: Run tests against BusyBox-based minimal environment
+        # SKIP growpart-lvm test as LVM tools are not available in BusyBox
         run: |
           mkdir /tmp/busybox-bin
           busybox --install -s /tmp/busybox-bin
           ln -s $(command -v flock mkfs.ext4 qemu-img qemu-nbd resize2fs sfdisk sgdisk) /tmp/busybox-bin
-          # Skip growpart: needs BusyBox >= 1.31, not available in Ubuntu yet.
-          # Skip mic: needs BusyBox >= 1.31, not available in Ubuntu yet.
-          sudo SKIP=mic,growpart,growpart-lvm PATH=$PWD/bin:/tmp/busybox-bin ./test/run-all
+          sudo SKIP=growpart-lvm PATH=$PWD/bin:/tmp/busybox-bin ./test/run-all
diff --git a/bin/ec2metadata b/bin/ec2metadata
index a67f6e6..a62c93b 100755
--- a/bin/ec2metadata
+++ b/bin/ec2metadata
@@ -36,15 +36,15 @@ except ImportError:
 
 instdata_host = "169.254.169.254"
 instdata_ver = "2009-04-04"
-instdata_url = "http://%s/%s" % (instdata_host, instdata_ver)
+instdata_url = f"http://{instdata_host}/{instdata_ver}"
 
 TOKEN_TTL_SECONDS = 21600
 TOKEN_HEADER = "X-aws-ec2-metadata-token"
 TOKEN_HEADER_TTL = "X-aws-ec2-metadata-token-ttl-seconds"
 
-session_token_url = "http://%s/%s/%s" % (instdata_host, 'latest', 'api/token')
+session_token_url = f"http://{instdata_host}/latest/api/token"
 
-__doc__ = """
+__doc__ = f"""
 Query and display EC2 metadata.
 
 If no options are provided, all options will be displayed
@@ -87,9 +87,9 @@ Options:
     --public-keys           display the openssh public keys
     --user-data             display the user data (not actually metadata)
 
-    -u | --url URL          use URL (default: %s)
+    -u | --url URL          use URL (default: {instdata_url})
 
-""" % instdata_url
+"""
 
 
 METAOPTS = ['ami-id', 'ami-launch-index', 'ami-manifest-path',
@@ -127,8 +127,7 @@ class EC2Metadata:  # pylint: disable=R0903
         if s.port is None:
             port = 80
         if not self._test_connectivity(addr, port):
-            raise Error("could not establish connection to: %s:%s" %
-                        (addr, port))
+            raise Error(f"could not establish connection to: {addr}:{port}")
         self._imdsv2_ensure_token()
 
     @staticmethod
@@ -154,7 +153,7 @@ class EC2Metadata:  # pylint: disable=R0903
         self.session_token = resp.read()
 
     def _get(self, uri, decode=True):
-        url = "%s/%s" % (self.burl, uri)
+        url = f"{self.burl}/{uri}"
         try:
             resp = urllib_request.urlopen(
                 urllib_request.Request(
@@ -198,7 +197,7 @@ class EC2Metadata:  # pylint: disable=R0903
 
             public_keys = []
             for keyid in keyids:
-                uri = 'meta-data/public-keys/%d/openssh-key' % int(keyid)
+                uri = f'meta-data/public-keys/{int(keyid)}/openssh-key'
                 public_keys.append(self._get(uri).rstrip())
 
             return public_keys
@@ -226,7 +225,7 @@ def display(metaopts, burl, prefix=False):
             value = "unavailable"
 
         if prefix:
-            print("%s: %s" % (metaopt, value))
+            print(f"{metaopt}: {value}")
         elif metaopt == "user-data":
             # We want to avoid binary blob corruption while printing as string
             print_binary(value)
@@ -239,8 +238,8 @@ def usage(s=None):
 
     msg = ""
     if s:
-        msg = "Error: %s\n" % s
-    msg += "Syntax: %s [options]\n" % sys.argv[0]
+        msg = f"Error: {s}\n"
+    msg += f"Syntax: {sys.argv[0]} [options]\n"
     msg += __doc__
     sys.stderr.write(msg + "\n")
     sys.exit(1)
diff --git a/bin/write-mime-multipart b/bin/write-mime-multipart
index fea9638..6fab346 100755
--- a/bin/write-mime-multipart
+++ b/bin/write-mime-multipart
@@ -83,15 +83,13 @@ def main():
 
         maintype, subtype = mtype.split('/', 1)
         if maintype == 'text':
-            fp = open(path)
-            # Note: we should handle calculating the charset
-            msg = MIMEText(fp.read(), _subtype=subtype)
-            fp.close()
+            with open(path, encoding='utf-8') as fp:
+                # Note: we should handle calculating the charset
+                msg = MIMEText(fp.read(), _subtype=subtype)
         else:
-            fp = open(path, 'rb')
-            msg = MIMEBase(maintype, subtype)
-            msg.set_payload(fp.read())
-            fp.close()
+            with open(path, 'rb') as fp:
+                msg = MIMEBase(maintype, subtype)
+                msg.set_payload(fp.read())
             # Encode the payload using Base64
             encoders.encode_base64(msg)
 
@@ -107,18 +105,20 @@ def main():
             ofile = sys.stdout.buffer
         else:
             ofile = sys.stdout
+        _write_output(ofile, outer, options)
     else:
-        ofile = open(options.output, "wb")
+        with open(options.output, "wb") as ofile:
+            _write_output(ofile, outer, options)
 
+
+def _write_output(ofile, outer, options):
+    """Write the MIME message to the output file."""
     if options.compress:
-        gfile = gzip.GzipFile(fileobj=ofile, filename=options.output)
-        gfile.write(outer.as_string().encode())
-        gfile.close()
+        with gzip.GzipFile(fileobj=ofile, filename=options.output) as gfile:
+            gfile.write(outer.as_string().encode())
     else:
         ofile.write(outer.as_string().encode())
 
-    ofile.close()
-
 
 if __name__ == '__main__':
     main()
diff --git a/test/test-growpart b/test/test-growpart
index 5e917be..ba3f84e 100755
--- a/test/test-growpart
+++ b/test/test-growpart
@@ -84,7 +84,7 @@ if [ -z "$out" ]; then
 	exit 1
 fi
 
-echo === growpart stderr ===
+echo "=== growpart stderr ==="
 cat "$errfile"
 
 echo "==== after ===="
diff --git a/tox.ini b/tox.ini
index 201402b..7613265 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,40 +8,22 @@ envlist =
     shellcheck
 
 [common]
-pyfiles =
-    bin/ec2metadata
-    bin/write-mime-multipart
-shfiles =
-    bin/cloud-localds
-    bin/growpart
-    bin/mount-image-callback
-    bin/resize-part-image
-    bin/vcs-run
-    test/test-growpart
-    test/test-growpart-fsimage
-    test/test-growpart-fsimage-middle
-    test/test-growpart-overprovision
-    test/test-growpart-lvm
-    test/test-growpart-start-matches-size
-    test/test-mic
-    test/run-all
-    tools/build-deb
-    tools/make-short-partition
-    tools/make-tarball
+pyfiles = bin/ec2metadata bin/write-mime-multipart
+shfiles = bin/cloud-localds bin/growpart bin/mount-image-callback bin/resize-part-image bin/vcs-run test/test-growpart test/test-growpart-fsimage test/test-growpart-fsimage-middle test/test-growpart-overprovision test/test-growpart-lvm test/test-growpart-start-matches-size test/test-mic test/run-all tools/build-deb tools/make-short-partition tools/make-tarball
 
 [testenv:flake8]
-deps = flake8==3.8.3
+deps = flake8==7.3.0
 commands = python3 -m flake8 {[common]pyfiles}
 
 [testenv:pylint]
-deps = pylint==2.5.3
+deps = pylint==4.0.4
 commands = python3 -m pylint {[common]pyfiles}
 
 [testenv:shellcheck]
 # shellcheck from Xenial is too old and doesn't support the --severity
 # argument; let's pull a newer version using shellcheck-py. This also
 # allows to pin the shellcheck version we check against.
-deps = shellcheck-py==0.7.1.1
+deps = shellcheck-py==0.11.0.1
 commands = shellcheck --severity=error {[common]shfiles}
 
 [testenv:tip-flake8]