I think there's something wrong with the version you have, because the RetroPie 4.5.1 image doesn't support the PI4 model (!). So which RetroPie version do you have ? As noted in https://retropie.org.uk/forum/topic/3/read-this-first, support for PI4 is still added to RetroPie so some things are not fully working - certainly not using the 4.5.1 version. EDIT: you can see the exact version by looking in the RetroPie-Setup script title:

It is Pi 3 b+ and RetroPie 4.5.3 (according to RetroPie Setup Script).

ExFat I can confirm it works.

So I finally figured it out. As usual it was a couple things, but none of them were as difficult as I was looking for. Everything was a little out of date, and because I was working on wifi, i figured id let it update everything over night. Turns out I hadnt done that since enabling usbrom service. After the update it (mostly) solved my problem, and after putting the pi on stretch instead of Jessie I'm good. Thanks @Efriim for going down the rabbit hole with me. I appreciated your help

Got it working, should have explored the set up more to see I needed to install the USB ROM service. Thanks

@che_don_john Ahh..gotcha..I was just curious. I see alot of people transferring via usb and have problems. So much easier using ssh. I was one of them when I first got my pi as I watched a youtube vid with no knowledge of ssh, and I found it took forever to transfer games via usb..lol . Glad you got it sorted !

@djpj3000 Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first https://retropie.org.uk/docs/Running-ROMs-from-a-USB-drive/

ignore this now, managed to get it working

Just put a folder called retropie-mount and a Roms folder. As long as those are there, it won’t copy anything. If you don’t have a Roms folder it will copy the roms folder from the sd to the usb memory.

Made some progress. Formatted the drive to NTFS and that sped things up considerably. I assume the wiki uses FAT32 specifically for flash drives and windows compatibility, though I'm not sure why they don't suggest exFAT. Right now I'm working on testing if exFAT is faster or slower than NTFS. I wish I'd known the usbromservice was more accepting of different file systems from the get go.

Mounting manually to: "sudo mount /dev/sda1 /media/usb" (instead of usb0) and restarting emulationstation doesn't trigger USB ROM Service as well. Also checked other pen drive. Same issue. Checked same raspberry pi with other OS on other card (OSMC). No issue. It's strictly Retropie OS issue!

The next one will be a Pi 3 B so I can have the option to include PS1 and N64 games as well as flexibility to try a bunch of other IoT stuff that's been on my mind for a couple years. :)

AlexMurphy is right, check out that link. It very well could be (as the link states) that your power supply isn't providing enough current. Also, if you are running a pi 3, if my memory serves me, wifi is built in. You not giving us any base information to work with makes things difficult to help. Also, if a better power supply doesn't work, I'm guessing that it's a hardware issue, not software, in which case, this is probably the wrong place to ask.

@dankcushions Thanks for that link. I will try it. Right now when I booted up the Pi it "mounted" the ROMs perfectly. So it seems to happen spontaneously - weird.

Ok i got it now. After deleting all folders in the retropie-mount folder on the stick and plugging it in on the rasperry and rebooting the system it seems that it starts copying again. Now everything seems to be copied correctly. The retropie menu is now here as well. Sorry for the big panic from me. Everything is fine now.

Changed fstab to: proc /proc proc defaults 0 0 /dev/mmcblk0p1 /boot vfat defaults 0 2 /dev/mmcblk0p2 / ext4 defaults,noatime 0 1 UUID=1918-2A41 /media/usb0 vfat auto,nofail,noatime,users,rw,uid=pi,gid=pi 0 0 /media/usb0/BIOS /home/pi/RetroPie/BIOS none auto,nofail,noatime,users,rw,uid=pi,gid=pi,bind 0 0 /media/usb0/roms /home/pi/RetroPie/roms none auto,nofail,noatime,users,rw,uid=pi,gid=pi,bind 0 0 more streamlined and I think 'bind' in the first of the three additional lines was the cause.

@jonnykesh said in Boot Script ordering for USB Mount and SplashScreen: @hooperre Have you considered turning the custom splash screen into a static video file? say 5 or ten seconds, whatever you feel is best. You say videos on the USB work fine so just turn the static image into a video file. Truth. Good shout. I'll probably just put them on the SD card unless I can dig into the splashscreen stuff and find out how to have it start later? Not sure. I know using Filezilla if I attempt to change permissions it doesn't work and I can't add them, but I know I can do it with Putty (chmod) it works. That's the only reason I preferred to stay on the USB.

@herb_fargus It's not a 3rd party image, it's someone's preconfigured noobs setup with 3 partitions: one with Retropie, one with Kodi, and one with Raspbian. It's still the default Retropie image on top of a headless raspbian os. It was done this way so you would have less overhead when running Retropie (rather than having Raspbian with the GUI with both Kodi and Retropie installed and running on it).

Sorry, I think it's working just fine. It's just that I thought that because I could access Retropie roms folder via LAN and see all the roms, that meant that they were on the SD card, but what I was actually doing was accesing the USB drive roms folder. Sorry!