Steps to fix this:-
Step1: Open Terminal
Step2: Type this command

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xed admin:///etc/initramfs-tools/initramfs.conf

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A file will open asking for your authentication. Provide it.
Step3: Find a line saying COMPRESS=lz4
Step4: Change COMPRESS=lz4 to COMPRESS=gzip
Step5: Save that file and close the file.
Step6: Now type this in the terminal:

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sudo update-initramfs -u

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Step7: Provide password
It will run some processes. After completion
Step8: Reboot your system