When loading modprobe hci_uart
it fail to load with message
modprobe: can't load module bluetooth (kernel.tclocal/net/bluetooth/bluetooth.ko): unknown symbol in module, or unknown parameter
dmesg result
1847.461673] bluetooth: Unknown symbol crypto_ecdh_key_len (err -2)
[ 1847.463004] bluetooth: Unknown symbol crypto_ecdh_encode_key (err -2)
[ 1847.529207] bluetooth: Unknown symbol crypto_ecdh_key_len (err -2)
[ 1847.530121] bluetooth: Unknown symbol crypto_ecdh_encode_key (err -2)
[ 1883.394850] bluetooth: Unknown symbol crypto_ecdh_key_len (err -2)
[ 1883.395332] bluetooth: Unknown symbol crypto_ecdh_encode_key (err -2)
[ 1883.469170] bluetooth: Unknown symbol crypto_ecdh_key_len (err -2)
[ 1883.470087] bluetooth: Unknown symbol crypto_ecdh_encode_key (err -2)
Comparing to original raspbian (bluetooth module on CM4 depends from ecdh_generic and ecc which are missing as kernel modules
Please add those modules as well to bluetooth package
PS. RPI3 works well without this (as soon as I understand is because RPI4/CM4 has bluetooth 5 support and RPI3 no)