For rooting the HTC Aria, you will need to use the “universal” method of rooting HTC Android 2.1 devices. It’s rather complicated but for those of you who must root your HTC Aria now, you can go here and follow directions on how to root the HTC Slide (which has been verified to work on the HTC Aria).
Un-zip the Package you Downloaded (This one)
Place the Contents of “update.zip” & “ota.zip” & “loop” into your Android SDK Tools folder.
Open Command Prompt or Terminal and CD to the SDK/Tools Directory.
Power on the Slide into the bootloader by Holding Down ( Volume Down + Power Button )
Now run your loop file from the prompt (either type “loop” in windows or “./loop.sh” in a *nix like) ( ./ Is used For OSX )
Once your loop is running in your prompt, select Recovery from the bootloader menu.
When recovery loads, you should Have an Offline Device. You can use ctrl+c to stop your script & see.
If this doesn’t happen, Power Off and try again..
Un-plug your USB cable from the back of your phone & Plug it back in for it to Detect ADB Correctly!!! This is an important step. At this point you can adb devices to see if you can see your device and that it is in recovery mode.
Hit Volume Up + Power button to Bring up the Selectable Menu
Select Update.zip from the menu. (This will fail, but we already know that! Select it anyway).
adb push ota.zip /sdcard/update.zip (*OSX users add a ./ in front of all terminal commands please.)
This is Very important!! Have this Command ready in your prompt before applying update.zip again!!
This is the Command, We do not Push this Yet adb push update.zip /sdcard
Hit run update.zip, as soon as you see a Little Bar appear under the text, push Enter to execute the command in your prompt (adb push update.zip /sdcard )
In successful, you should see Clockwork Recovery & you Now have Su & Superuser.apk Installed! You can Now Reboot Your Phone into the OS to verify.
If unsuccessful, repeat steps 11 & 12.
After rooting, you will need to install a “rooted” ROM, refer to this guide on xda-developers.com