Note from Wololo: This tutorial was initially published by /Talk member YumYumOfTheYum, as part of our monthly tutorial contest. YumYumOfTheYum won the best PS Vita tutorial prize in June (a $10 PSN Code) for his entry. You can find the original post here.
This is for PSM Dev Unity packaged by Major.Tom & Mr Gas. Credits to them, and also all you coders in the scene. Big thanks !
Install Mozilla Thunderbird (portable version also OK, thanks pythonista for clarifying).
Open the “test2.eml” file included in the package using Thunderbird then send the email to your email. You can send it to yourself, btw.
Copy the directory “UNITY” into PSAVEDATA/blahblahblah/UNITY in your PSAVEDATA folder .. note blahblahblah is your device unique identifier.
Then copy the package using Content Manager. It will show as PSM UNITY INSTALL (>3.20).
Rebuild database before anything else (power off then R+power+PS button).
Tap any game that needs updating but don’t open it.
Start update for the game by tapping the upper leftmost icon in that game’s “page”.
Pause the running update (open your notification bubble in LiveArea then tap … then “pause”).
Open Vita email app, then open the email sent earlier by yourself. If it’s correct, you will have 2 attachments showing as images.
Tap image 1 (left). An error message will appear, just close the app (NOT the error message).
Re-open Vita email app, then open again that email.
Tap image 2 (right). An error message will appear, just close the app (NOT the error message) just like before.
Turn off Wi-Fi.
Open your notification bubble in LiveArea, then tap on the message showing failed update.
For you guys noticing 96kb (or whatever) size in the Vita content manager app after copying the save data, don’t worry, it’s really 27-something MB. It is shown as 96kb because apparently the Vita system did not read the size of the subfolders.
Also, apparently you need QCMA instead of OCMA for successful file transfer (h/t Dr.GiggleZ and AlexTwolf).
If you’re on 3.30+, apparently you need to update the PSM Dev Unity app first. Just do it.
If your Vita says “you must update the system software”, just shutdown and refresh database. Restart in airplane mode (h/t tinostar91).
Some people reported that the game update must be paused right after it is initiated, but that seems not to be the case (h/t tinostar91).
Outlook doesn’t work, Hotmail doesn’t work (h/t RonnChyran and SaltySticks). For Gmail, you need to either enable 2-step verification and use app specific password, or allow access to less secure apps.
PSM Runtime can also be used for update payload (h/t RikuKurai).
Any game on a cart can also be used, as long as it requires an update (h/t Xplic1T).
Edited for a few important points forgotten, 2nd edit for additional infos learned by people in this thread. Thanks, everyone!