Be very careful, don't touch any dtb files and make sure you only change start.elf and fixup.dat (which are start4x.elf and fixup4x.dat in the RPi firmware repo). Otherwise chances are high you'll brick your LibreELEC installation.
Read more about it here: Pi4 USB Boot is coming soon!!!! YAAAY
so long,
Hias
Dont do that, you are bricking your LibreELEC installation.
Only replace start.elf and fixup.dat, eg with the script or instructions in the linked post, and make sure no other start/fixup files are present.
It may work for you now but if you have other start/fixup files on your SD card your RPi won't be using the one needed for LibreELEC and on later LibreELEC updates you'll still be using that old version which can cause a lot of headache for you.
USB boot is working fine here with the May 27 firmware and bootloader versions.
so long,
Hias
Display MoreDont do that, you are bricking your LibreELEC installation.
Only replace start.elf and fixup.dat, eg with the script or instructions in the linked post, and make sure no other start/fixup files are present.
It may work for you now but if you have other start/fixup files on your SD card your RPi won't be using the one needed for LibreELEC and on later LibreELEC updates you'll still be using that old version which can cause a lot of headache for you.
USB boot is working fine here with the May 27 firmware and bootloader versions.
so long,
Hias
So I update my firmware pieeprom to 15 june 2020. After that I made a fresh install on an usb stick 3.1 with LE 9.2.3
When I put in my pi4 and power it up the screen is saying that he is missing some files. But after some seconds LE is starting up. Where could I find the correct files to solve this issue?
Where could I find the correct files to solve this issue?
You do know the whole RPi-USB booting thing is still in beta... Right?
So I update my firmware pieeprom to 15 june 2020. After that I made a fresh install on an usb stick 3.1 with LE 9.2.3
When I put in my pi4 and power it up the screen is saying that he is missing some files. But after some seconds LE is starting up. Where could I find the correct files to solve this issue?
This is perfectly normal, LE stores the firmware files under a different name. Just ignore the warnings.
so long,
Hias
You do know the whole RPi-USB booting thing is still in beta... Right?
it is official launched and is stable now and not beta.
This is perfectly normal, LE stores the firmware files under a different name. Just ignore the warnings.
so long,
Hias
So I am all done? Because you wrote some comments ago to replace the start.elf and fixup.dat files.
At this moment I do not have an ssd. Is there anyway to compare the usb stick with the sd card? I just want to know if the sd card
at this moment faster is then the usb or not.
it is official launched and is stable now and not beta.
Okay, I stand corrected. I'm not on the daily Raspberry news band. 
So I am all done? Because you wrote some comments ago to replace the start.elf and fixup.dat files.
That was some time ago before the 9.2.3 release. 9.2.3 has recent enough firmware files and you don't need to replace anything.
so long,
Hias
That was some time ago before the 9.2.3 release. 9.2.3 has recent enough firmware files and you don't need to replace anything.
so long,
Hias
I got it thank you. Well is there a tip to check the speed while running in LE with the usb stick and sd card?
