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Well i have my blobs saved but i don't know how to downgrade from 12.4 to ios 12.2, i have an iphone 6.

You would need to set a nonce. Which would need a jailbreak. And an exploit for such has not been publicly released.

So: No.

As Chr0nicT said, you need a Nonce Setter which is based on a tfp0 exploit because it has to unlock the NVRAM before it can set the generator. You'll need to wait for such exploit.

I will close the thread now as there's not much else that can be done.