i was just messing around with qcma and made some progress. here is what i did in steps:
1. download these files
https://mega.nz/#!yQVACArR!2KK4lNrsPO_g ... cCcGvknq1o
2.add the psp2updat.pup from 3.60/full/ to your qcma update folder as well as a web hosting server on your ip
3.edit your psp2-updatelist.xml so it says this:
Code: Select all
<?xml version="1.0" encoding="UTF-8"?>
<update_data_list>
<region id="us">
<np level0_system_version="01.600.000" level1_system_version="03.600.000" level2_system_version="03.600.000" map="03.600.000" />
<np_d level0_system_version="01.600.000" level1_system_version="03.600.000" level2_system_version="03.600.000" map="03.600.000" />
<version system_version="04.600.000" label="3.60">
<update_data update_type="full">
<image size="133676544">*your ip server address here*/3.60/full/PSP2UPDAT.PUP</image>
</update_data>
</version>
</region>
</update_data_list>
4.enable flight mode on psvita and select "system update", then select "update by connecting to a pc"
5. it will show the new version screen with "version 3.60" so go through the steps for a normal update
6. the system update will start and then go to an error stating "This system software cannot be used with this system (c1-6562-9)"
if anyone could reproduce this maybe try hex editing the update pup or something. i don't know how hex editing works though.

i am sure however if we all band together we can get a working downgrade!
