My name is Tanmoy Roy. Thanks for this awesome 3uTools which looks very promising although I am yet to witness the power of that yet. I am pretty sure with the expert guidance from you, I will be able to use the tool.
Apologies for posting my problem in intro section but in order to post in relevant section, I will require no less than 20 posts. Running in bit of urgency of the moment and thus posting here.
So, here is the situation:-
I have iPad Mini 3 WiFi only currently powered by iOS 8.3..i know pretty outdated

I would like to flash iOS 9.3.3 as I understand there is a stable untethered Jail break solution for that in place
I downloaded the iPad4,7_9.3.3_13G34_Restore firmware from the ipsw site
I launched the latest 3uTools, switched my iPad to DFU mode
I headed to Pro Flash under Flash & JB option
Import Firmware and then clicked Flash
Below is the excerpt from the log-
06:18:59 Verifying firmware file
06:19:26 MD5 value of firmware : 4A461CB55E6DA52FEE3D44760CE15FAC
06:19:26 Filename of firmware : iPad4,7_9.3.3_13G34_Restoreipsw
06:19:26 MD5 value is different from official firmware, maybe firmware has damaged
06:19:26 Unzipping firmware file
06:20:55 Apple server no longer supports the flash of this firmware version
06:20:55 Failed to flash
06:20:55 If the device doesn't exit current mode
06:20:55 Please hold the HOME and POWER buttons for about 10 seconds
06:20:55 Flash and jailbreak of apple device, please visit official website of 3uTools
06:20:55 Elapsed Time: 00:01:56
Please let me know what went wrong? Is it not possible to flash iOS 9.3.3 via the 3uTools?
Grace>> I have also mailed you in the 3utools gmail id. Please respond.
Thanks,
Tanmoy.