RT 4.19.71-rt24-v7l+ brakes USB on Raspberry PI 4 OS (Version 11/01/2021)

Instal done after cloning the sdcard to usb key, but uname -a i see nothing changed ???

now i try apt-get upgrade

This is no go.
On Raspberry Pi4 4Gb il lock the boot process on the rainbow CPU test

Before Installing the .deb
Linux raspberrypi 5.4.83-v7l+ #1379 SMP Mon Dec 14 13:11:54 GMT 2020 armv7l GNU/Linux

pi@raspberrypi:~/Downloads $ sudo apt-get install ./linux-image-5.4.83-rt48-v7l+_5.4.83-rt48-v7l+-4_armhf.deb
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'linux-image-5.4.83-rt48-v7l+' instead of './linux-image-5.4.83-rt48-v7l+_5.4.83-rt48-v7l+-4_armhf.deb'
The following packages will be REMOVED:
raspberrypi-kernel
The following NEW packages will be installed:
linux-image-5.4.83-rt48-v7l+
0 upgraded, 1 newly installed, 1 to remove and 0 not upgraded.
Need to get 0 B/19.6 MB of archives.
After this operation, 213 MB disk space will be freed.
Do you want to continue? [Y/n] Y
Get:1 /home/pi/Downloads/linux-image-5.4.83-rt48-v7l+_5.4.83-rt48-v7l+-4_armhf.deb linux-image-5.4.83-rt48-v7l+ armhf 5.4.83-rt48-v7l+-4 [19.6 MB]
(Reading database ... 98460 files and directories currently installed.)
Removing raspberrypi-kernel (1.20210108-1) ...
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 5.4.83+ /boot/kernel.img
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 5.4.83-v7+ /boot/kernel7.img
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 5.4.83-v7l+ /boot/kernel7l.img
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 5.4.83-v8+ /boot/kernel8.img
Selecting previously unselected package linux-image-5.4.83-rt48-v7l+.
(Reading database ... 90311 files and directories currently installed.)
Preparing to unpack .../linux-image-5.4.83-rt48-v7l+_5.4.83-rt48-v7l+-4_armhf.deb ...
Adding 'diversion of /boot/./System.map-5.4.83-rt48-v7l+ to /usr/share/rpikernelhack/./System.map-5.4.83-rt48-v7l+ by rpikernelhack'
Adding 'diversion of /boot/./kernel7l.img to /usr/share/rpikernelhack/./kernel7l.img by rpikernelhack'
Adding 'diversion of /boot/./config-5.4.83-rt48-v7l+ to /usr/share/rpikernelhack/./config-5.4.83-rt48-v7l+ by rpikernelhack'
Unpacking linux-image-5.4.83-rt48-v7l+ (5.4.83-rt48-v7l+-4) ...
Setting up linux-image-5.4.83-rt48-v7l+ (5.4.83-rt48-v7l+-4) ...
update-initramfs: Generating /boot/initrd.img-5.4.83-rt48-v7l+

After apt-get upgrade usb boot killed.

Try again on the sdcard instal kernel and edit /boot/config-rt.txt but this file seem to be missing :
vmlinuz-5.4.83-rt48-v7l+

Al
see
forum.linuxcnc.org/9-installing-linuxcnc...-2gb?start=20#195017
the usb fail on rpi-os is connected to memory
all rpi's fail at >=4meg
in the above forum posy i show a fix and where the fix came from
it works for me on my rpi4 4meg
thx
tomp

alkabal wrote: After apt-get upgrade usb boot killed.

Try again on the sdcard instal kernel and edit /boot/config-rt.txt but this file seem to be missing :
vmlinuz-5.4.83-rt48-v7l+

The kernel deb installs a new kernel7l instead.

tjtr33 wrote: Al
see
forum.linuxcnc.org/9-installing-linuxcnc...-2gb?start=20#195017
the usb fail on rpi-os is connected to memory
all rpi's fail at >=4meg

It isn't that simple. The 5.4-rt48 kernel works fine on my 4GB Pi400.

That kernel includes every patch from raspberry Pi up to last night, it should be the most up-to-date possible kernel, with all patches.

The links all lead to issues with the arm64 (64-bit) kernels. The -rt48 kernel is a 32-bit kernel.

Does the stock 32-bit kernel work with the Pi4-8GB?

I think that the only rational choice at this point it probably to abandon "official" Raspberry Pi support.