Oracle Linux: How To Downgrade UEK5 To UEK4 kernel

The solution in this guide can be applied on Virtual and Physical Machine. Solution 1. If you have a UEK4 kernel still available, boot that and then delete the UEK5 kernel(s). yum remove $(rpm -qa kernel-uek | grep 4.1.35) Note: Please check the kernels that are going to be removed before you hit "y". 2. If you don't have a UEK4 kernel, then install it. yum install kernel-uek-4.1.12* Or yum install *4.1.12* 3. Boot that UEK4 kernel and then remove the UEK5 kernel as shown in step 1. 4. Please ensure you've disabled the UEK5 repo. Once you've disabled the UEK5 repo, so run the command below. yum list extras 5. If that shows up anything that was in the UEK5 repo then "yum downgrade ..." for those rpms will downgrade them to their earlier version. Note: Do them all at once: yum downgrade's dependency calculations don't work (well, it doesn't have any as such). It is highly recommended to back-up the state of the system prior to any patching: For Oracle Guest VM Backup, please refer to this KM Doc Oracle VM: How To Backup And Restore A VM Guest (domU) Domain On Oracle VM 3.x (Doc ID 1477421.1) For other Guest VM such as VMware and Microsoft Hyper-V, please engage with the Corresponding Support Vendor. For the Physical Machine, please back-up the system to an external storage (e.g. tape, storage snapshot, storage dedup, or any other third party backup solution, etc.)