How to revert back to the original version (pre-Epic Games)

Ever since the game updated itself to Re-Elected people have been having issues with it. Some couldn't load certain savegames, others couldn't play for too long, and others (like myself) couldn't even play because it kept crashing at startup. To remedy this, we'll "downgrade" the game to its latest patch before the mess that is the Re-Elected patch in order for it to work again.
All DLCs work, alongside with Workshop and non-Workshop mods!

IMPORTANT: Regarding the latest update

The sriv_legacy beta branch finally works. You don't need to do the steps in this guide to play the original version, but if you feel the need to fully revert it and you don't trust the legacy branch, stick to this guide.
It's important to clarify that Re-Elected breaks with too many mods installed, so the original version is always suggested if you want to mod the game. However, if you didn't own the DLCs before the game changed its Steam name and version to Re-Elected, you won't have them in the original version of the game. Therefore, you'll have to choose what you prefer having when thinking about using the original version, or Re-Elected: mods, or DLCs. The choice is yours.

Step 1 - Console

Boot up Steam (obviously), and open the developer console by pressing Windows+R, then pasting steam://open/console in the "Run" box and pressing Enter. Afterwards, you should see a new tab pop up on Steam: Console.

Step 2 - Downloading the old files

Now that you have the developer console, paste the following in it: download_depot 206420 206421 32002699204955846
These are the main SRIV files (packfiles, videos, etc.) from the last patch before the abysmal Re-Elected patch. They're 8,670 megs (almost 8,70 GB!), so they'll take some time to download.
Once they download, paste the following in Steam's console: download_depot 206420 206422 6013726710204312506
This is just 6 megs, and it's the old SRIV executable. You need it to play SRIV without the patch; the new executable won't work with the old files.
Update: Here's what you need to install if you're playing on Linux. Thanks to DW_Taya for the info!
Instead of downloading the 206422 depot, paste download_depot 206420 206426 641706767085429081 in the console to download the Linux files.
Update 2: If you bought the game on Australia, the 206422 depot won't work, as it claims you're missing a license for it. Simply use the 206425 depot by pasting the following line in the console: download_depot 206420 206425 3029064039942818866
Thanks to Patriarch for the info!

Step 3 - Adding the old files to your SRIV folder

Before you do anything with the old files, head to your Saints Row IV installation folder (by default, it's Steam -> steamapps -> common -> Saints Row IV) and delete the following files: SaintsRowIV.exe, sr_hv.exe, SaintsRowIV.ini & EOSSDK-Win64-Shipping.dll (thanks to RedAISkye for notifying me about the last one!)
Now it's time to locate the pre Re-Elected files. They're in your Steam installation folder, under Steam -> steamapps -> content -> app_206420. There, you'll find the old files under the "depot_206421" and "depot_206422" folders. Now copy and paste the content of both folders in your Saints Row IV folder. Replace all the new files with the old ones (they're 100 as far as I remember).
Update: If you want, you can also delete binkw64.dll & steam_api64.dll, since they're used for x64 applications; since the original SaintsRowIV.exe is a x32 application, they go unused. Thanks to RedAISkye for the info!

Step 4 - Playing the damn game

Once you've done all the previous steps, start the game in Steam and enjoy SRIV in its original state. No Epic Online Services, no Epic Games Accounts required, nothing. Just you, your homies, and a bunch of aliens that are in desperate need of getting killed.

Step 5 (optional) - Original library assets

The Re-Elected patch changed every SRIV library asset to fit Re-Elected's artwork change. If you're like me, and you're looking for the authentic SRIV experience (or you just don't like the Re-Elected artwork because it's not as appealing as the original), here are the links to replace every new asset with the old ones:

• Small capsule https://cdn.cloudflare.steamstatic.com/steam/apps/206420/capsule_231x87.jpg?t=1486042711
  
• Big capsule https://cdn.cloudflare.steamstatic.com/steam/apps/206420/capsule_616x353.jpg?t=1486042711
  
• Header https://cdn.cloudflare.steamstatic.com/steam/apps/206420/header.jpg?t=1486042711
  
• Cover https://cdn.cloudflare.steamstatic.com/steam/apps/206420/library_600x900.jpg?t=1567457337
  
• Background https://cdn.cloudflare.steamstatic.com/steam/apps/206420/library_hero.jpg?t=1567457337
  
• Logo https://cdn.cloudflare.steamstatic.com/steam/apps/206420/logo.png?t=1567457336

Aditionally, if these links direct you to the new library assets, I've uploaded the original assets in a .rar file just in case, here's the link for them: https://www(dot)mediafire(dot)com/file/unsl4pwc2z307k7/SRIVoriginallibrary.rar/file
Sorry for having to replace the dots with... well, "(dot)", but it's to circumvent Steam's external link deletion feature.
You have two methods of replacing the new assets with the old ones.

• Via Steam: In the library's main page (the one where all your games are shown), locate Saints Row IV's box and right click it, then Administrate, then Add custom artwork. Replace Re-Elected's cover art with the old one, and you're done.
  For the background and logo, select Saints Row IV from your library and simply right click the area where the game's background and logo are (above the Play button). You'll get three options: Add custom artwork, add custom logo and change logo position. The image listed as "background" in my guide is the game's artwork, and the logo... well, you get the idea :p
  The original logo's position was positioned in the top of the background.
  
• Via file replacement: Go to Steam -> appcache -> librarycache and simply paste the original library assets in there. You'll be asked if you want to replace the old assets with these ones; just replace them. The thing is... I haven't tested this particular method. It should work with no problems, however, but you may need to restart Steam in order for it to take effect. Any updates SRIV may recieve could also reinstate the current artwork, so you'll have to change it again if that happens.

Step 6 (optional) - Preventing Steam from updating SRIV

In case your game updates to the Re-Elected version after you downgrade, don't worry. You can force Steam to not update a game via console commands, and here's the guide that shows how to do so:
https://steamcommunity.com/sharedfiles/filedetails/?id=885555151
Thanks to Kasey for the info!

End

That's it! Hope this guide worked for you, I can at least confirm it worked flawlessly for me. Just to clarify once again, all DLCs work alongside Workshop and non-Workshop mods. Don't forget that along the old files we just pasted, there's also the game's config file (display.ini), so if your graphic configurations are different, don't worry. It's because of that.
Share this guide with your friends and just anyone in general that's having issues with Saints Row IV, and let's hope Volition and Deep Silver get their ♥♥♥♥ together and fix this ASAP.
Thanks for reading!
Update: Co-op works flawlessly! Thanks to Thiago_GC for letting me try it out with him.

[LAM1206]

after all these machinations the game simply does not start. I did everything as instructions says, replaced everything, deleted unnecessary exe files. I tried to run the exe from the game root, but it gives an error that there are no Steam dll files and steaminternal_createinterface

[FantasyChronicle]

i attempted this and the initial console commands dont... work :/ it fails for me. i made sure to follow the steps exactly so im a little lost now :C i really want to play again, how can this be so broken that it requires so much fiddling on the consumer side to fix it???

[rlyehG]

Thank you

[Jewish Santa]

Depot download failed : error writing chunk for "C:\Program Files (x86)\Steam\steamapps\content\app_206420\depot_206421\packfiles\pc\cache\characters.vpp_pc"

[Destin_Star]

is there a video for this? this is confusing for me i am not a programmer.

[sj_490]

Remember the days when you didn't have to choose between mods and official dlc's? Good times...

[[now yuo see] CINEK OTW]

Whenever Epic touches sth - it's fucking done. I lost all the stats from saves XD!

[Asirelith]

Why the 2 last guy say that you can downgrade in properties of the game on Steam, it's literally written in the guide, the first section... hello?

[MC Chase]

You can just downgrade via the branc system, just right click SR4, go to properties, then to beta versions, then choose sriv_legacy. Do you REALLY need to do this developer console thing??

[jacob123443211]

You can also downgrade by using library→right click sr4→properities→beta versions→choose sriv_legacy instead of none