Custom Firmware With Baseband 6.15 May 2026 150 Common Chinese Character List [Free PDF]

Use this tool to add tone marks to pinyin or to convert tone number (e.g. hao3) to tone marks.

Although you can use the red buttons to add tone marks, we highly recommend you use the number method (e.g. hao3) for speed and placement of the accent above the correct vowel. [Hint: Type "v" for "ü"]
Note: You do not need to use this tool to enter pinyin in this dictionary.

This is not a current tutorial (it is obsolete and dangerous for modern phones), but rather a of a legendary jailbreak artifact from the iPhone 3G/3GS era. The Forbidden Firmware: Why Baseband 06.15 Destroyed and Saved the iPhone 3G In the pantheon of jailbreak lore, certain numbers carry weight. 01.59.00. 05.13.04. But none strikes fear and nostalgia into the hearts of veteran iOS hackers quite like 06.15.00 .

Between 2009 and 2011, if you owned a locked iPhone 3G or 3GS on AT&T or O2, you faced a wall: software unlocks were dead. Apple had patched every vulnerability. The only way to use a prepaid SIM card on vacation was to install a custom firmware that did the unthinkable—update the baseband to an iPad’s firmware.

The warning text was stark: “This is irreversible for iPhone 3G. For iPhone 3GS, downgrading is impossible.”