diff --git a/sys/BootSync/bootsync.py b/sys/BootSync/bootsync.py
index 774ba1b..b42195d 100755
--- a/sys/BootSync/bootsync.py
+++ b/sys/BootSync/bootsync.py
@@ -15,14 +15,15 @@ from lxml import etree
 
 
 class BootSync(object):
-    def __init__(self, cfg = None, *args, **kwargs):
+    def __init__(self, cfg = None, validate = True, *args, **kwargs):
         if not cfg:
             self.cfgfile = '/etc/bootsync.xml'
         else:
             self.cfgfile = os.path.abspath(os.path.expanduser(cfg))
-        self.ns = '{http://git.square-r00t.net/OpTools/tree/sys/BootSync/}'
+        self.ns = None
         self.cfg = None
         self.xml = None
+        self.schema = None
         # This is the current live kernel.
         self.currentKernVer = self._getRunningKernel()
         # This is the installed kernel from the package manager.
@@ -33,15 +34,13 @@ class BootSync(object):
         self.dummy_uuid = None
         self.syncs = {}
         ##
-        self.getCfg()
+        self.getCfg(validate = validate)
         self.chkMounts()
         self.chkReboot()
         self.getHashes()
         self.getBlkids()
-        # self.sync()
-        # self.writeConfs()
 
-    def getCfg(self):
+    def getCfg(self, validate = True):
         if not os.path.isfile(self.cfgfile):
             raise FileNotFoundError('Configuration file {0} does not exist!'.format(self.cfgfile))
         try:
@@ -53,6 +52,19 @@ class BootSync(object):
             # self.logger.error('{0} is invalid XML'.format(self.cfgfile))
             raise ValueError(('{0} does not seem to be valid XML. '
                               'See sample.config.xml for an example configuration.').format(self.cfgfile))
+        self.ns = self.cfg.nsmap.get(None, 'http://git.square-r00t.net/OpTools/tree/sys/BootSync/')
+        self.ns = '{{{0}}}'.format(self.ns)
+        if validate:
+            if not self.schema:
+                from urllib.request import urlopen
+                xsi = self.cfg.nsmap.get('xsi', 'http://www.w3.org/2001/XMLSchema-instance')
+                schemaLocation = '{{{0}}}schemaLocation'.format(xsi)
+                schemaURL = self.cfg.attrib.get(schemaLocation,
+                                                ('http://git.square-r00t.net/OpTools/plain/sys/BootSync/bootsync.xsd'))
+                with urlopen(schemaURL) as url:
+                    self.schema = url.read()
+            self.schema = etree.XMLSchema(etree.XML(self.schema))
+            self.schema.assertValid(self.xml)
         return()
 
     def chkMounts(self):
@@ -278,6 +290,11 @@ class BootSync(object):
 
 def parseArgs():
     args = argparse.ArgumentParser(description = ('Sync files to assist using mdadm RAID arrays with UEFI'))
+    args.add_argument('-V', '--no-validate',
+                      dest = 'validate',
+                      action = 'store_false',
+                      help = ('If specified, do not attempt to validate the configuration file (-c/--cfg) against'
+                              'its schema (otherwise it is fetched dynamically and requires network connection)'))
     args.add_argument('-c', '--cfg',
                       dest = 'cfg',
                       default = '/etc/bootsync.xml',
diff --git a/sys/BootSync/bootsync.xsd b/sys/BootSync/bootsync.xsd
index 4ab4c7d..6ea587e 100644
--- a/sys/BootSync/bootsync.xsd
+++ b/sys/BootSync/bootsync.xsd
@@ -24,6 +24,28 @@
         </xs:restriction>
     </xs:simpleType>
 
+    <xs:simpleType name="hashtype_choice">
+        <xs:restriction base="xs:string">
+            <xs:enumeration value="false"/>
+            <!-- https://docs.python.org/3/library/hashlib.html#hash-algorithms -->
+            <xs:enumeration value="md5"/><!-- Not available on FIPS-compliant Python -->
+            <xs:enumeration value="sha1"/>
+            <xs:enumeration value="sha224"/>
+            <xs:enumeration value="sha256"/>
+            <xs:enumeration value="sha384"/>
+            <xs:enumeration value="sha512"/>
+            <xs:enumeration value="blake2b"/>
+            <xs:enumeration value="blake2s"/>
+            <!-- The below are only available for more recent versions of system's OpenSSL. -->
+            <xs:enumeration value="sha3_224"/>
+            <xs:enumeration value="sha3_256"/>
+            <xs:enumeration value="sha3_384"/>
+            <xs:enumeration value="sha3_512"/>
+            <xs:enumeration value="shake_128"/>
+            <xs:enumeration value="shake_256"/>
+        </xs:restriction>
+    </xs:simpleType>
+
     <xs:element name="bootsync">
         <xs:complexType>
             <xs:sequence>
@@ -56,11 +78,14 @@
                                         <xs:extension base="relpath">
                                             <xs:attribute name="isKernel" type="xs:boolean"
                                                           use="optional" default="false"/>
+                                            <xs:attribute name="hashtype" type="hashtype_choice"
+                                                          use="optional" default="md5"/>
                                         </xs:extension>
                                     </xs:simpleContent>
                                 </xs:complexType>
                             </xs:element>
                         </xs:sequence>
+                        <xs:attribute name="hashtype" type="hashtype_choice" use="optional" default="md5"/>
                     </xs:complexType>
                     <xs:unique name="filechk_unique">
                         <xs:selector xpath="bootsync:file"/>
@@ -76,9 +101,12 @@
                                     <xs:attribute name="target" type="relpath" use="required"/>
                                     <!-- TODO: make this optional? -->
                                     <xs:attribute name="pattern" type="xs:string" use="required"/>
+                                    <xs:attribute name="hashtype" type="hashtype_choice"
+                                                  use="optional" default="md5"/>
                                 </xs:complexType>
                             </xs:element>
                         </xs:sequence>
+                        <xs:attribute name="hashtype" type="hashtype_choice" use="optional" default="md5"/>
                     </xs:complexType>
                     <xs:unique name="syncpath_unique_source">
                         <xs:selector xpath="bootsync:path"/>
diff --git a/sys/BootSync/sample.config.xml b/sys/BootSync/sample.config.xml
index b982ae9..43e564c 100644
--- a/sys/BootSync/sample.config.xml
+++ b/sys/BootSync/sample.config.xml
@@ -17,33 +17,72 @@ SEE prep.txt FOR WHAT MUST BE DONE BEFORE RUNNING BOOTSYNC.
         <part path="/dev/sdb1" mount="/mnt/boot1"/>
         <part path="/dev/sdd1" mount="/mnt/boot2"/>
     </partitions>
-    <!-- If specified, the files in this container are checksummed to determine if a sync is required.
-         If fileChecks isn't provided, we will always sync no matter what.
+    <!--
+         If fileChecks isn't provided, we will still sync syncPaths (which IS required).
          These files will be evaluated to and synced to the ESP partitions with the same relative path.
          i.e. (part[@mount])/(file)
 
+         fileChecks[@hashtype] attribute is used to checksum all <file> children,
+         unless they specify their own hashtype attribute (the default is hashtype="md5" for speed optimizations).
+
+         Guaranteed valid hashtype values are:
+
+            sha1
+            sha224
+            sha256
+            sha384
+            sha512
+            blake2b
+            blake2s
+
+         If you have a non-FIPS-compliant Python (you very most likely do), the following hashtype is also available:
+
+            md5
+
+         If you have a recent enough OpenSSL (and python3), you have the additional hashtype values available:
+
+            sha3_224
+            sha3_256
+            sha3_384
+            sha3_512
+            shake_128
+            shake_256
+
+         Additionally, the value "false" is always available to disable hashing for a specific <file> object or to set
+         the default. No checksumming will be done in this case and the file will always be overwritten on every run.
+
+         This is *highly not recommended* for solid-state disks or if you have large files you plan on syncing to
+         the alternate ESPs (e.g. loop-mounted ISO/IMG files).
+
          "isKernel" is by default false, but if true it is treated specially to get a kernel version.
          This is to notify you if a reboot is required. If no <file> item is isKernel="true", no reboot requirement
          detection will be done.
-         Only *the last* <file> with isKernel="true" listed is used as the kernel identifier. -->
-    <fileChecks>
-        <!-- RELATIVE paths to /boot -->
+         Only *the last* <file> with isKernel="true" listed is used as the kernel identifier.
+    -->
+    <fileChecks hashtype="sha1">
+        <!-- RELATIVE paths to /boot on your / mount. -->
         <file>initramfs-linux.img</file>
         <file>intel-ucode.img</file>
         <file>memtest86+/memtest.bin</file>
-        <file isKernel="true">vmlinuz-linux</file>
+        <file isKernel="true" hashtype="sha512">vmlinuz-linux</file>
     </fileChecks>
-    <!-- These are system paths to sync to the ESPs. They are synced recursively.
+    <!--
+        These are system paths to sync to the ESPs. They are synced recursively.
+
+            "hashtype" is also supported for syncPaths and path objects just as the same with fileChecks
+            and file objects (see above).
+
             "source" should be absolute.
             "target" should be relative (to the ESP mount).
-            "pattern" is a regex to match to restrict *filenames* to sync. Use ".*" for all files. -->
-    <syncPaths>
+            "pattern" is a regex to match to restrict *filenames* to sync. Use ".*" for all files.
+    -->
+    <syncPaths hashtype="sha1">
         <!-- For example, these are grub theme files. -->
         <path source="/usr/share/grub/themes" target="grub/themes" pattern=".*"/>
         <!-- These are grub modules - specifically, UEFI. -->
         <path source="/usr/lib/grub/x86_64-efi" target="grub/x86_64-efi" pattern="^.*\.(mod|lst|sh)$"/>
         <!-- And these are ISO files, in case you're like me and do loop mounting in Grub for rescue situations.
              (e.g. https://wiki.archlinux.org/index.php/Multiboot_USB_drive#Using_GRUB_and_loopback_devices) -->
-        <path source="/boot/iso" target="iso" pattern="^.*\.(iso|img)$"/>
+        <path hashtype="false" source="/boot/iso" target="iso" pattern="^.*\.(iso|img)$"/>
     </syncPaths>
 </bootsync>
\ No newline at end of file