How to app unlock your HTC S621 Windows Mobile Smartphone
October 2nd, 2007 by Ross McKillop |
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This tutorial will guide you in “app unlocking” your HTC S621. I was hoping to create something like ‘how to app unlock a windows mobile smartphone’, but after spending hours and hours trying to unlock my phone, I’ve discovered there are possibly hundreds of different ways - no two are the same, and not all will work for all phones. I can only confirm that the following method works for Rogers (a Canadian mobile provider) customers using the HTC S621. It may work for other Smartphones as well.
App unlocking will allow you to install “unsigned” 3rd party software. If you’ve ever received the error “Installation was unsuccessful. The program or setting cannot be installed because it is not digitally signed with a trusted certificate”, this tutorial is for you.

You’ll need to download these 2 files - SP_AllowCertificateInstall.cab and regeditSTG2.exe.
- Upload SP_AllowCertificateInstall.cab to your device (or download it directly to your device). Save the file on your devices main memory, not on a mini-SD card. Use the file manager to navigate to SP_AllowCertificateInstall.cab and run it. Click Done when it’s done.
- Now upload regeditSTG2.exe to your HTC. Use the file manager to navigate to regeditSTG2.exe and run it.
- Now from inside the registry editor, navigate to HKEY_LOCAL_MACHINESecurityPoliciesPolicies
- When you get to the second Policies folder, click the Values button.
- Highlight the 00001001 entry and then select it.
- Change the Value data: from 2 to 1, and then click Done.
- Now highlight the 00001005 entry and then select it.
- Change the Value data: from 16 to 40, and then click Done.
- Now scroll down to the 00001017 entry, highlight it and then select it.
- The Value data: may already be set to 144. If it is, leave it alone (just click Done). If it’s not, set it to 144 - then click Done.
- Now you can close down the registry editor and reboot your phone (turn the power off, then back on again). Your HTC S621 is now app unlocked and ready to install unsigned software.














12 Responses to “How to app unlock your HTC S621 Windows Mobile Smartphone”
By Jose Carvalho on Oct 11, 2007 | Reply
Ross
Great tutorial. I thought I had the same problem on my HTCS621 and I did the same thing. But the message I keep getting is “this installation file is not appropriate for this device”.
I have been unable to install any 3rd party software on my smartphone.
Do you have any idea on how I can fix it?
Thanks
By Chris on May 3, 2008 | Reply
Hey, I’ve done all you’ve said to do, but I am still unable to install pnester. Still get the the program is not intended for this device message.
By Ross McKillop on May 3, 2008 | Reply
@Chris:
Exactly the same phone? HTC S621? Which version of Windows Mobile (5, 6 or 6.1)?
Ross
By Chris on May 4, 2008 | Reply
Yes, the exact same phone running windows mobile 6.0. I recently retried it though and it worked perfectly. I guess I made a mistake along the way the first few times. Thanks again!