graf_chokolo: Swap HDD w/o Reformatting - 改機

http://goo.gl/C1NjP

來看看graf_chokolo放出的技術資料

HDD

* ENCDEC peripheral device is used for HDD encryption/decryption
主機上有一顆ENCDEC晶片作為加解密引擎，即時對硬碟的資料進行加解密動作

* Write request is first passed to ENCDEC device for encryption.
When ENCDEC device is done, it calls a callback and passes the
encrypted data to the callback. The callback writes the encrypted
data with ATA WriteDMAExt command to HDD.
當系統發出寫入要求時，ENCDEC會將資料加密，然後回傳給系統讓系統透過寫
入ATA WriteDMAExt 指令寫入硬碟。

* When a storage device request is processed by HV, Storage
Subsystem checks if cryptography is enabled for the storage device.
當存取儲存裝置的請求由HV發出時，控制儲存裝置的子系統會檢查加密機制是
否啟動。

* HV checks 1 byte of data owned by the storage device and when
the value of this flag is not 0 then it uses encryption/decryption.
HV只檢查 1個位元，該位元是加密開啟與否的旗標，如果是 0的話就關閉加密
機制。

* By setting this flag to 0 at runtime, encryption/decryption of
storage devices can be disabled at runtime.
因此，將該旗標設成 0，就可以將硬碟加密關閉。

* We could patch lv1.self so that encryption/decryption of
storage devices is disabled permanently.
同時，我們可以透過修改lv1.self檔案，永遠關閉加密機制（而不需要每次開
機都操作關閉的程序）。

* HDD sectors can be both decrypted and encrypted with HV calls
透過HV呼叫，也可以將硬碟的某個特定磁區加密或是解密。

UFS2

* Superblock starts at sector 0x80.
UFS2檔案系統的超級區塊（不知道是不是這樣翻）從0x80磁區開始

* At the end of the superblock structure you will find UFS2
signature 0x19540119.
超級區塊末端會有UFS2檔案系統的指紋0x19540119

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