1. install EP1004-CUSA00411_00-GTAVDIGITALDOWNL-A0100-V0105.pkg
2. dump it with xvortex dumper 1.6 and split option
3. go to cusa00411-app/sce_sys/param.sfo and open it with orbis-pub-sfo.exe (faketools 1.2) and change master version 1.05 to 1.00 and save it.
4. create gp4 with gengp4 and build the pkg with orbis-pub-gen.
5. now you've got your own EP1004-CUSA00411_00-GTAVDIGITALDOWNL-A0100-V0100.pkg keep it because we need it later.
6. use orbis-pub-chk and extract jhonnys v1.21 update with passcode 00000000000000000000000000000000 to the cusa00411-patch folder
7. now you have got 2 folders. image0 and sc0. you have to integrate the content of sc0 to image0/sce_sys. there will be a folder called "app" in the sc0 folder. there is a playgo-chunk.dat in it which you will have to put in image0/sce_sys and overwrite it with the existing one. then you can delete the folder "app" because we don't need it to be in image0/sce_sys.
8. now you've got your patch files in the right structure (compare with the file structure from your previous made dump of cusa00411-app if you are unsure) but they are still inside the cusa0411-patch/image0/... so now you have to take all files from image0 and move them to cusa0411-patch. now delete the empty image0 folder.
9. use gengp4 and create gp4 from cusa0411-patch folder.
10. build the patch gp4 with orbis-pub-gen. it will be successful because it finds the EP1004-CUSA00411_00-GTAVDIGITALDOWNL-A0100-V0100.pkg you created in step 5.
11. when its finished, you've got your game.pkg in v1.00 and your own created v1.21 patch.pkg from jhonny and both install fine!
Thanks to Sashka