LoRa technology, crucial for low-power wide-area networks, faces significant performance degradation at extremely low signal-to-noise ratios (SNRs). We present LoRaFlow, a novel approach using rectified flow to reconstruct high-quality LoRa signals in challenging noise conditions. Unlike existing neural-enhanced methods focused on classification, LoRaFlow recovers the signal itself, maintaining compatibility with standard dechirp algorithms. Our method combines a hybrid neural network architecture, synthetic data generation, and robust augmentation strategies. This minimally invasive enhancement to LoRa infrastructure potentially extends operational range and reliability without overhauling existing systems. LoRaFlow opens new possibilities for robust IoT communications in harsh environments and its core methodology can be generalized to support various communication technologies.