diff --git a/src/LibHac/Fs/Shim/SdCardPrivate.cs b/src/LibHac/Fs/Shim/SdCardPrivate.cs
new file mode 100644
index 00000000..3980d785
--- /dev/null
+++ b/src/LibHac/Fs/Shim/SdCardPrivate.cs
@@ -0,0 +1,80 @@
+using System;
+using LibHac.Diag;
+
+namespace LibHac.Fs.Shim;
+
+public static class SdCardPrivate
+{
+    public const int SdCardCidSize = 16;
+    public const int SdCardCidPnmSize = 5;
+    public const int SdCardCidOidSize = 2;
+
+    private const int SdCardCidMdtMonthCodeIndex = 0;
+    private const int SdCardCidMdtYearCodeLowerIndex = 0;
+    private const int SdCardCidMdtYearCodeUpperIndex = 1;
+    private const int SdCardCidPsnIndex = 2;
+    private const int SdCardCidPrvIndex = 6;
+    private const int SdCardCidPnmIndex = 7;
+    private const int SdCardCidOidIndex = 12;
+    private const int SdCardCidMidIndex = 14;
+
+    public static int GetMdtMonthCodeFromSdCardCid(ReadOnlySpan<byte> cid)
+    {
+        Abort.DoAbortUnless(cid.Length >= SdCardCidSize);
+
+        return cid[SdCardCidMdtMonthCodeIndex] & 0xF;
+    }
+
+    public static int GetMdtYearCodeFromSdCardCid(ReadOnlySpan<byte> cid)
+    {
+        Abort.DoAbortUnless(cid.Length >= SdCardCidSize);
+
+        return ((cid[SdCardCidMdtYearCodeUpperIndex] & 0xF) << 4) | ((cid[SdCardCidMdtYearCodeLowerIndex] & 0xF0) >> 4);
+    }
+
+    public static int GetPsnFromSdCardCid(ReadOnlySpan<byte> cid)
+    {
+        Abort.DoAbortUnless(cid.Length >= SdCardCidSize);
+
+        return (cid[SdCardCidPsnIndex + 3] << 24) |
+               (cid[SdCardCidPsnIndex + 2] << 16) |
+               (cid[SdCardCidPsnIndex + 1] << 8) |
+               cid[SdCardCidPsnIndex];
+    }
+
+    public static int GetPrvFromSdCardCid(ReadOnlySpan<byte> cid)
+    {
+        Abort.DoAbortUnless(cid.Length >= SdCardCidSize);
+
+        return cid[SdCardCidPrvIndex];
+    }
+
+    public static void GetPnmFromSdCardCid(Span<byte> destination, ReadOnlySpan<byte> cid)
+    {
+        Abort.DoAbortUnless(cid.Length >= SdCardCidSize);
+        Abort.DoAbortUnless(destination.Length >= SdCardCidPnmSize);
+
+        for (int i = 0; i < SdCardCidPnmSize; i++)
+        {
+            destination[SdCardCidPnmSize - i - 1] = cid[SdCardCidPnmIndex + i];
+        }
+    }
+
+    public static void GetOidFromSdCardCid(Span<byte> destination, ReadOnlySpan<byte> cid)
+    {
+        Abort.DoAbortUnless(cid.Length >= SdCardCidSize);
+        Abort.DoAbortUnless(destination.Length >= SdCardCidOidSize);
+
+        for (int i = 0; i < SdCardCidOidSize; i++)
+        {
+            destination[SdCardCidOidSize - i - 1] = cid[SdCardCidOidIndex + i];
+        }
+    }
+
+    public static int GetMidFromSdCardCid(ReadOnlySpan<byte> cid)
+    {
+        Abort.DoAbortUnless(cid.Length >= SdCardCidSize);
+
+        return cid[SdCardCidMidIndex];
+    }
+}
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