Step 1)
Open iTunes and connect the iPhone.
Step 2)
Press and hold the Home button and the Sleep/Wake button at the same time.
Step 3)
After exactly 10 seconds release the Sleep/Wake button. Continue holding the home button until you iTunes pops up a message telling you that it has detected an iPhone in recovery mode.
Step 4)
The iPhone screen will remain black. Also bear in mind, that in some cases it may take a few attempts to get your iPhone into DFU mode.
The question is : which is better, HTC Desire or iPhone 4 ? A small compare bellow in the table.
| Make/Model | HTC Desire | iPhone 4 |
| OS | Android | iPhone OS |
| Form |
Block | Block |
| Networks | 850/900/1800/1900 WCDMA 900/2100 | GSM 850 / 900 / 1800 / 1900, HSDPA 850 / 1900 / 2100 |
| Dimensions |
119 x 60 x 12 | 114.3 x 58.7 x 9.4 |
| Weight | 135g | 140g |
| Talk Time |
6 hours 40m | |
| Stand By |
340 hours | |
| Internal Memory | 512 MB. Expandable up to 32 GB with microSD card | 16/32 GB |
| Memory Slot | YES | NO |
| Camera | YES | YES |
| Camera Resolution | 5.0MP | 5.0MP |
| Camera Flash | YES | YES |
| Battery | 1400 mAh | 1320mAh |
| Screen Size | 3.7 inch | 3.5 inch |
| GSM Band | Quad | Quad |
| Video Camera | YES | YES |
| Bluetooth | YES | YES (handsfree only) |
| MMS | YES | YES |
| Radio | YES | NO |
| HSDPA | YES | YES |
| YES | YES | |
| Web Browsing | Android Webkit 3.1 | Mobile Safari browser |
| 3G | YES | YES |
| WiFi | YES | Wi-Fi 802.11b/g/n |
| Multimedia (audio/video) |
AAC, AMR, OGG, M4A, MID, MP3, WAV, WMA 3GP, 2G2, MP4, WMV |
AAC, MP3, AIFF, WAV
M4V, MP4, MOV, MPEG-4 |
