Runner trains LoRA directly on quantized GGUFs — no PyTorch, no FP16 base needed

ZenZombie117 · reddit · 2026-10-14

A Redditor shares xyntetik-runner, an open-source tool that trains LoRA adapters directly on the quantized GGUF weights you serve — no PyTorch, transformers, or FP16 parent model required. On CPU, the training forward pass is the serving forward pass, so the adapter is trained on the exact weights it will run on.

Usage (commands included):

Caveat: 4-bit adapters "disappear" when merged into weights, so the tool refuses such merges by default. Author validated on Qwen3-4B Q4KM with before/after tool-call scores, noting results may not generalize. Very practical for local fine-tuning and on-device deployment.

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