Ann123_sg, don't worry about bricking the unit, 1st gen iphones are the safest to tweak:
1) Connect the unit to itunes to fully sync all contacts, calendars, sms, notes, app data, and photos.
2) In itunes, right click on the iphone's name and select "backup iphone" to do it one more time.
3) Transfer all the photos in your iphone's camera roll to your computer.
4) Download these onto your computer's desktop:
- Redsn0w 0.9.4 (
Windows) or (
Mac)
-
Both 1st gen iphone firmwares:
(
3.1.3) and put it in a folder named "firmware 3.1.3"
and
(
3.1.2) and put it in a folder named "firmware 3.1.2"
-
Both bootloader files:
(
3.9)
and
(
4.6)
5) In itunes, hold down the Shift keyboard key (if using Windows) or Option key (if using a Mac) and click the "Restore" button. A file browsing window will pop-up.
6) Select the firmware 3.1.
3 file you downloaded. Let itunes finish restoring the device to stock firmware 3.1.3. It will reboot when it's done and give you a unsupported sim card prompt. Relax.
7) Launch Redsn0w 0.9.4 and when it asks to select the firmware to use, select the firmware 3.1.
2 file you downloaded. Click "Next" then follow the prompts.
8) When you get to the screen asking which options to pick, put a checkmark on only 2 items:
- Install Cydia
- Unlock
9) If asked for the bootloaders, browse to each of the 2 bootloaders you downloaded respectively.
10) Click "Next", follow the onscreen instructions. Hold the iphone in your hand and prepare to do a button press combination of doing a DFU boot by following the onscreen instructions/guide prompts Redsn0w will display on its window.
11) Let Redsn0w do its thing and after the last reboot, it will bring you to your unlocked and activated iphone.
12) Launch itunes and when asked if you want to set it up as a new phone or to restore from a backup, choose the option to restore from your previous backup and let itunes do its thing. It might do a reboot in the middle of the process, just let it be and wait for itunes to say everything is finished before doing anything else.
* You can also choose to set it up as a new phone and sync back your contacts/calendar/synced photos, but you will lose your sms, notes, and camera roll photos.
13) Once done sync the iphone with the computer one last time. That's it. You can now download apps from the Appstore and sync it into the unit.
14) If you want to use Cydia, set your iphone's autolock to "never" and then launch Cydia. It will say "Reorganizing" then will respring afterwards. Launch cydia again, select "User (Graphical Only)" on the pop-up. Another pop-up will say there are essential upgrades for cydia. Select "Update all" and it will ask to restart cydia again. If you're not going to install anything close Cydia and that's it.
Here's a video demo of the process.
Here are
Windows and
Mac iClarified tutorials for you to browse as a guide should you still need to do so.
If you still find these instructions a bit hard to follow, you can commission someone else to do it by bringing the iphone to
Decode.
That should be everything you'll ever need to upgrade your unit to firmware 3.1.3 (the last firmware the 1st gen iphone supports).
Forums 
. It was unlocked and jailbroken ages ago (from AT&T). I'm using a Qtel SIM (Qatar) right now but it's useless since my iPhone can't read it. Can you please help me unlock and jailbreak it again.
I've tried some softwares but can't fix it. I would love to have the FW also upgraded. Any suggestions or assistance would be great. Thank you. 
