I did some more tests and I guess I found out what was causing this problem. After cloning the sd card everything works fine until I copy my rom's to the ssd. I just attached the ssd with the usb adapter to my Ubuntu machine and copied everything there to get faster speeds. But it seems that this method changes something in the filesystem that then causes all sorts of problems when booting from the ssd. I now simply copied the sd card to the ssd again to get a fresh start and then copied everything with SFTP and now everything seems to be running fine.

@mitu Thank you for the clarification.

thank you. I did some dirty work and managed to prepare a small uSD image so i can boot to USB and load a 128 GB image. thank.

I just tried my MicroSD card into a USB 2.0 MicroSD card reader and booted into Retropie. It's giving me faster speeds on 4K random read and write. WTF?! LOL

Not really retropie based, but you could try Demul or nulldc. Just download the zip files, not the installer. You probably have to reconfigure the bios and Iso folders each time you open it on a different device.

PINN allows you to install Retropie directly to an USB stick. https://www.raspberrypi.org/forums/viewtopic.php?t=142574

@priest282 also 2.5a is the specification for a pi 3 WHAT ARE THE POWER REQUIREMENTS? Raspberry Pi 3 Model B Recommended PSU current capacity 2.5A Maximum total USB peripheral current draw 1.2A

@dankcushions "(i believe i encountered it when a transfer via OSX/samba failed)" I did use my Macbook to Transfer the Data, I should check at home what changes if I use my PC to transfer the data!

@Schfifty said in USB boot; memory size incorrect: @madmodder123 Thank you! I will try this when I get home. Would something like Knoppix work as well? I think I'm going to try SSH first so I don't have to take the usb out of the Pi Yeah pretty much any linux distro will work

@retox I wrote something about this a while ago. New USB Drive boot method in latest FW It's still in beta and is not developed by the RetroPie team. Raspian that is built on Debian is developed by the Raspberry Pi foundation. Any bug's are to be reported to the Raspberry pi github

@zoop THANKS A LOT !!!! ;)

I just followed the guide here. https://github.com/raspberrypi/documentation/blob/master/hardware/raspberrypi/bootmodes/msd.md You can follow the thread on it over at raspberrypi.org https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=155167