[Samsung Galaxy Fold Guides, News, & Discussion] iBowToAndroid:
For those who don't know, F900U is the model number of all of the US carrier versions of the Galaxy Fold. The F900U1 is the model number of the same device, but sold by Samsung SIM unlocked and with no carrier bloatware. Firmware is 100% interchangeable among these models: any U or U1 firmware version can be flashed to any U or U1 device at any time, assuming that you're not trying to downgrade the bootloader. A "U to U" or "U1 to U1" flash does not require a factory reset, but changing from one firmware to the other will require one. Also, U firmware is identical for the 4 base files (AP, BL, CP, CSC) for each individual build, no matter which carrier it comes from. So if you download 2 different carrier versions of the exact same build, the 4 base files will be identical. Where the firmware differs is in the USERDATA file - that's where the carrier bloatware and customizations reside.

Manual Odin flashing is designed for those who:

- want to manually update to a newer version of U firmware on their U device, either because they don't want to wait for their carrier's OTA or because OTAs aren't working on their device, or a different carrier got a new feature/patch before they did

- want to flash U1 firmware to their U device

- want to convert from U1 firmware to carrier U firmware

- want to convert from one carrier's U firmware (with all apps and bloatware) to a different carrier's U firmware (with all apps and bloatware)

For those who aren't already aware, anyone can now download firmware for almost any Samsung device any time that they want, via SamFirm or Frija. There are threads and info about them here on XDA so I won't waste time explaining - do a search if you're not already familiar with these tools. But AT&T doesn't allow their firmware to be publicly available (for any of their devices). I pay for a subscription to a site that gets the official releases (usually) before they hit SamFirm/Frija, and also gets me access to AT&T firmware, so that's where my files come from. However, I don't have unlimited bandwidth on the site, and it's also quite time consuming to download the files, zip them up, and upload them to AFH. And, I do threads like this for every single Sx and Note x model - so I won't be uploading every single version. I'll definitely do at least one build per bootloader level though.

This is not a "beginner's guide to Odin flashing"-type post/thread, so I won't list basic, step-by-step instructions. My threads are geared towards those who already know what they're doing. If you're new to manually flashing Samsung firmware, I recommend you consult one of the "beginner's" posts/threads - there are tons of them here on XDA.

U firmware: https://www.androidfilehost.com/?w=files&flid=293117

U1 firmware: https://www.androidfilehost.com/?w=files&flid=293118

Happy flashing!

Notes:

- DON'T QUOTE THE OP WHEN YOU REPLY, kthx :)

- I compress extra small for space and bandwidth savings. The default Windows extractor can't handle it, so you'll need a 3rd party tool like 7zip, WinRAR, etc

- My naming method for Android File Host folders is: build - bootloader - Android version.

So "SAT - 1 - 9.0" means the full build number ends in SAT, it's bootloader version 1, and Android 9.0. When bootloader and Android versions increment, the first build to have those changes will have its folder notated appropriately.

- HOME CSC file keeps data intact; using the other CSC will wipe data.

- I pay for a subscription to a site that gets beta builds and also sometimes gets the official releases before they hit SamFirm, so that's where any of my files come from. I will only be posting versions that I get early access to, and USERDATAs that aren't available on SamFirm or Frija (AT&T). The newest/latest firmware files for all carriers other than AT&T can always be obtained via SamFirm and Frija.

- For USERDATAs (all the others are self explanatory):

AIO = Cricket

CCT = Xfinity Mobile (Comcast)

CHA - Spectrum Mobile (Charter)

TMK = Metro PCS

- the correct procedure for switching from one carrier's firmware to another is:

1. Flash full U1 firmware package including non HOME CSC

2. Upon boot, insert a SIM of the carrier whose firmware you want

3. Watch for the popup that says "reboot to apply new carrier settings" etc, and do it

4. After that restart completes, reboot back to Download mode and flash the full U firmware package, with the USERDATA file of the carrier whose firmware you want