Thanks.

ubuntu@ubuntu:~$ sudo dpkg -i linux-image-5.3.0-1008-raspi2_5.3.0-1008.9+newupdate_arm64.deb
(Reading database ... 97816 files and directories currently installed.)
Preparing to unpack linux-image-5.3.0-1008-raspi2_5.3.0-1008.9+newupdate_arm64.deb ...
Unpacking linux-image-5.3.0-1008-raspi2 (5.3.0-1008.9+newupdate) over (5.3.0-1008.9+newupdate) ...
Setting up linux-image-5.3.0-1008-raspi2 (5.3.0-1008.9+newupdate) ...
Processing triggers for linux-image-5.3.0-1008-raspi2 (5.3.0-1008.9+newupdate) ...
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-5.3.0-1008-raspi2
Using DTB: bcm2711-rpi-4-b.dtb
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
flash-kernel: deferring update (trigger activated)
/etc/kernel/postinst.d/zz-flash-kernel:
Using DTB: bcm2711-rpi-4-b.dtb
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
flash-kernel: deferring update (trigger activated)
Processing triggers for flash-kernel (3.98ubuntu5) ...
Using DTB: bcm2711-rpi-4-b.dtb
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
flash-kernel: installing version 5.3.0-1008-raspi2
Taking backup of vmlinuz.
Installing new vmlinuz.
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
Taking backup of initrd.img.
Installing new initrd.img.
Generating boot script u-boot image... done.
Taking backup of boot.scr.
Installing new boot.scr.
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.

ubuntu@ubuntu:~$ sudo dpkg -i linux-modules-5.3.0-1008-raspi2_5.3.0-1008.9+newupdate_arm64.deb
(Reading database ... 97816 files and directories currently installed.)
Preparing to unpack linux-modules-5.3.0-1008-raspi2_5.3.0-1008.9+newupdate_arm64.deb ...
Unpacking linux-modules-5.3.0-1008-raspi2 (5.3.0-1008.9+newupdate) over (5.3.0-1008.9+newupdate) ...
Setting up linux-modules-5.3.0-1008-raspi2 (5.3.0-1008.9+newupdate) ...
Processing triggers for linux-image-5.3.0-1008-raspi2 (5.3.0-1008.9+newupdate) ...
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-5.3.0-1008-raspi2
Using DTB: bcm2711-rpi-4-b.dtb
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
flash-kernel: deferring update (trigger activated)
/etc/kernel/postinst.d/zz-flash-kernel:
Using DTB: bcm2711-rpi-4-b.dtb
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
flash-kernel: deferring update (trigger activated)
Processing triggers for flash-kernel (3.98ubuntu5) ...
Using DTB: bcm2711-rpi-4-b.dtb
Installing /lib/firmware/5.3.0-1008-raspi2/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/5.3.0-1008-raspi2/./bcm2711-rpi-4-b.dtb
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
flash-kernel: installing version 5.3.0-1008-raspi2
Taking backup of vmlinuz.
Installing new vmlinuz.
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.
Taking backup of initrd.img.
Installing new initrd.img.
Generating boot script u-boot image... done.
Taking backup of boot.scr.
Installing new boot.scr.
Taking backup of bcm2711-rpi-4-b.dtb.
Installing new bcm2711-rpi-4-b.dtb.

sudo nano /boot/firmware/config.txt 
    #total_mem=3072
sudo reboot
...
Linux ubuntu 5.3.0-1008-raspi2 #9+newupdate SMP Mon Oct 21 18:09:52 CST 2019 aarch64 aarch64 aarch64 GNU/Linux

working usb

sorry to waste your time!