In Deployment Solution 6.9 SP6 and 7.5, the Linux Preboot Environment (aka Linux Automation) was updated to a newer version of the Linux kernel. Without going into details as to why, it was determined that 2GB RAM minimum would be required. Due to this change, any system that has <2GB RAM can no longer use Linux PE to boot to automation - in many cases lower RAM is why Linux was chosen as the automation environment in the first place.
To get around this issue, many have resorted to retaining older versions of Linux PE for older systems, but then also requiring the new Linux PE for UEFI and other newer systems. We now have a better solution for this, which allows the use of the newer kernel for both groups of systems.
Disclaimer: This method is currently officially unsupported.
Here are the steps to modify the Linux PE to adjust the minimum required RAM: