diff --git a/api/v1alpha1/ionoscloudmachine_types.go b/api/v1alpha1/ionoscloudmachine_types.go
index 7fff27a..25edeb0 100644
--- a/api/v1alpha1/ionoscloudmachine_types.go
+++ b/api/v1alpha1/ionoscloudmachine_types.go
@@ -42,7 +42,6 @@ type IONOSCloudMachineSpec struct {
 	AvailabilityZone *string `json:"availabilityZone,omitempty"`
 	// The total number of cores for the enterprise server.
 	// +kubebuilder:validation:Minimum=1
-	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="Cores is immutable"
 	Cores *int32 `json:"cores"`
 	// CPU architecture on which server gets provisioned; not all CPU architectures are available in all datacenter regions; available CPU architectures can be retrieved from the datacenter resource; must not be provided for CUBE servers.
 	// +kubebuilder:validation:MinLength=1
diff --git a/config/crd/bases/infrastructure.cluster.x-k8s.io_ionoscloudmachines.yaml b/config/crd/bases/infrastructure.cluster.x-k8s.io_ionoscloudmachines.yaml
index 83d5c0e..6cfd57e 100644
--- a/config/crd/bases/infrastructure.cluster.x-k8s.io_ionoscloudmachines.yaml
+++ b/config/crd/bases/infrastructure.cluster.x-k8s.io_ionoscloudmachines.yaml
@@ -83,9 +83,6 @@ spec:
                 format: int32
                 minimum: 1
                 type: integer
-                x-kubernetes-validations:
-                - message: Cores is immutable
-                  rule: self == oldSelf
               cpuFamily:
                 description: CPU architecture on which server gets provisioned; not
                   all CPU architectures are available in all datacenter regions; available
diff --git a/config/crd/bases/infrastructure.cluster.x-k8s.io_ionoscloudmachinetemplates.yaml b/config/crd/bases/infrastructure.cluster.x-k8s.io_ionoscloudmachinetemplates.yaml
index 7e205e4..b125033 100644
--- a/config/crd/bases/infrastructure.cluster.x-k8s.io_ionoscloudmachinetemplates.yaml
+++ b/config/crd/bases/infrastructure.cluster.x-k8s.io_ionoscloudmachinetemplates.yaml
@@ -94,9 +94,6 @@ spec:
                         format: int32
                         minimum: 1
                         type: integer
-                        x-kubernetes-validations:
-                        - message: Cores is immutable
-                          rule: self == oldSelf
                       cpuFamily:
                         description: CPU architecture on which server gets provisioned;
                           not all CPU architectures are available in all datacenter