I use .pcengines.ch (apu2) hardware and set up a pxe environment autoinstall works with ubuntu-20.04.3-live-server-amd64.iso but it fails when upgrading to ubuntu-20.04.4-live-server-amd64.iso.

Log of www-server for ubuntu-20.04.3-live-server-amd64.iso:

2022/07/26 11:52:59 [notice] 1#1: start worker process 27

192.168.41.20 - - [26/Jul/2022:11:54:16 +0000] "GET /ksfiles/ubuntu-20.04.3-live-server-amd64.iso HTTP/1.1" 200 1261371392 "-" "Wget" "-"

192.168.41.20 - - [26/Jul/2022:11:55:23 +0000] "GET /ksfiles/ubuntu-20.04.3-live-server-amd64.iso HTTP/1.1" 200 1261371392 "-" "Cloud-Init/21.2-3-g899bfaa9-0ubuntu2~20.04.1" "-"

192.168.41.20 - - [26/Jul/2022:11:56:03 +0000] "GET /ksfiles/ubuntu-20.04.3-live-server-amd64.iso HTTP/1.1" 200 1261371392 "-" "Cloud-Init/21.2-3-g899bfaa9-0ubuntu2~20.04.1" "-"

192.168.41.20 - - [26/Jul/2022:11:56:08 +0000] "GET /ksfiles/apu21/meta-data HTTP/1.1" 200 0 "-" "Cloud-Init/21.2-3-g899bfaa9-0ubuntu2~20.04.1" "-"

192.168.41.20 - - [26/Jul/2022:11:56:08 +0000] "GET /ksfiles/apu21/user-data HTTP/1.1" 200 1916 "-" "Cloud-Init/21.2-3-g899bfaa9-0ubuntu2~20.04.1" "-"

192.168.41.20 - - [26/Jul/2022:11:56:08 +0000] "GET /ksfiles/apu21/vendor-data HTTP/1.1" 301 169 "-" "Cloud-Init/21.2-3-g899bfaa9-0ubuntu2~20.04.1" "-"

192.168.41.20 - - [26/Jul/2022:11:56:08 +0000] "GET /ksfiles/apu21/vendor-data/ HTTP/1.1" 200 198 "-" "Cloud-Init/21.2-3-g899bfaa9-0ubuntu2~20.04.1" "-"

Log of www-server for ubuntu-20.04.4-live-server-amd64.iso:

192.168.41.20 - - [26/Jul/2022:12:24:49 +0000] "GET /ksfiles/ubuntu-20.04.4-live-server-amd64.iso HTTP/1.1" 200 1331691520 "-" "Wget" "-"

192.168.41.20 - - [26/Jul/2022:12:25:59 +0000] "GET /ksfiles/ubuntu-20.04.4-live-server-amd64.iso HTTP/1.1" 200 1331691520 "-" "Cloud-Init/21.4-0ubuntu1~20.04.1" "-"

192.168.41.20 - - [26/Jul/2022:12:26:36 +0000] "GET /ksfiles/ubuntu-20.04.4-live-server-amd64.iso HTTP/1.1" 200 1331691520 "-" "Cloud-Init/21.4-0ubuntu1~20.04.1" "-"

I find the Error message in the boot log on Console:

[  OK  ] Reached target Host and Network Name Lookups.

[  138.071529] Out of memory: Killed process 1125 (cloud-init) total-vm:2661804kB, anon-rss:2475148kB, file-rss:2784kB, shmem-rss:0kB, UID:0 pgtables:4916kB oom_score_adj:0

[FAILED] Failed to start Initial cl…ob (metadata service crawler).

See 'systemctl status cloud-init.service' for details.

my pxe config file looks like:
content of pxelinux.cfg/01-XX-XX-XX-XX-XX-XX:

    DEFAULT install

    LABEL install

      KERNEL vmlinuz

      INITRD initrd

      APPEND root=/dev/ram0 ramdisk_size=1500000 ip=dhcp url=http://192.168.41.5/ksfiles/ubuntu-20.04.4-live-server-amd64.iso autoinstall ds=nocloud-net;s=http://192.168.41.5/ksfiles/apu21/ console=ttyS0,115200n8 earlyprint=serial,ttyS0,115200

To me it looks like the cloud-init process is killed during boot due to OOM. is there a significant difference between 20.04.03 and 20.04.04 ?
how can I fix this?