[Firecube 3rd gen import]

I can only tell you what is working for me and see if it will work for you as well. I have a 2nd gen Fire TV Cube which has the same Fire TV OS7 as the 3rd gen based on Android 9, and I am using Launchbox with the 32-bit version of RetroArch side-loaded, (Fire OS7 can't take 64-bit apps and you need to change the default RetroArch to the 32-bit version for every system added). I'm using it with a 64GB Sandisk USB drive (with an OTG cable) with no problem. I copied the data folder for Launchbox from its default location to /storage/(USB drive number)/Android/data/com.unbrokensoftware.launchbox using X-Plorer. I later deleted the default data folder for Launchbox off the internal drive and it continued to work fine. (The usb drive must be formatted in Fat 32 on the Fire TV Cube for external use only. Formatting it for internal use causes problems using the current Fire TV OS7. The USB drive kept randomly disconnecting, and apps moved to the USB drive could not longer be found. You also won't be able to see the USB drive in X-Plorer if you format it as internal.) Since we are using the same Fire TV OS, it might just be you are choosing the wrong location to move the data folder to where you don't have permission to access it. The one I chose above is working for me. So I have /storage/(USB drive number)/Android/data/com.unbrokensoftware.launchbox/LaunchBox(All data and images). Both RetroArch and LaunchBox are running from internal storage with about 30GB from RetroArch data, images and games on the USB drive and 6.2GB of data and images from LaunchBox on the USB drive. I still have over 4GB of space on the internal drive left for apps, (had my cube for well over a year) and over 20GB left on the USB. I have tons of everything Nintendo 64 and lower, but only have a few arcade and Playstation games since they take up so much space. You can get more advice on how and where to move the data folder just by doing a search for "launchbox move data folder". Hope that helps.

[Cant find my hdd !!!!!! (Android)]

I used to an app developer, but no more.  I had a battery app, but starting with Android 11, Google introduced all sorts of problems (including for us the OS no longer knowing when extra large batteries were fully charged), but more importantly introducing problematic storage access issues for developers in the name of "security".  They also started making silly mandates of developers, and so a year ago I pulled my paid app from the Google Play store.  One of the mandates was we had to take the word "free" out of the name of the free version of the app even though it was.  Shortly afterwards, Amazon renamed one of their apps "Freevee".  Still there on the Play Store today.  Uh-huh...

I have a refurbished 2nd gen Fire TV Cube with Fire OS 7 (based on Android 9) and have been running the latest side-loaded 32-bit RetroArch (with almost all roms on an USB drive with an OTG cable) along with LaunchBox for the past year with no problem.  My suggestion to those who want to run emulation from Android is to get a cheap refurbished device with Android 9 or lower on it and use that.  Only the newest 2nd gen Fire TV 4K sticks are running Fire OS8 based on Android 10 and 11.  Even the 3rd gen Fire TV Cube is still running Fire OS7 (Android 9).  Anyway, don't blame LaunchBox.  Blame Google.

[New version of Launchbox "downloading core" causing issues]

Ahh...  So that's why I'm getting so many black screens now...  BTW, RetroArch has a PS2 version that installs on systems that have FreeMcBoot, and the Atari 2600 (Stella 2014) and Colecovision (Gearcoleco) cores have been broken since v1.13, (that's from 11-19-2022) and the current "stable" version of PS2 RetroArch is on v1.17.  (Tried it again a week ago, and nope, still broke.  Crashes you to the PS2 browser.)  So the "newest" cores for those systems have been broken for over a year on PS2 RetroArch.  So just because RetroArch has a newer core out on Android, it doesn't mean it's going to continue to work as it did before.  I agree it should be an option to download the new core if you want to try it, but not a forced thing.  And if you upgrade the app itself through LaunchBox, is Launchbox doing a check to see to see if the version you have installed of "RetroArch" is 64 bit or 32 bit before trying to upgrade?  Because if you get RetroArch.apk from the libretro buildbot site, it's my understanding that you are downloading the 64-bit version, whereas if you down "RetroArch" from the Amazon App Store you are downloading a 32-bit version because all except the latest FireTV's, Fire Sticks and Fire Cubes only support 32-bit apps.