Worked on the comfyanonymous/ComfyUI repository to address a device management issue affecting users with AMD GPUs in multi-GPU environments. Focused on backend development using Python, the work involved fixing the handling of the --cuda-device flag to ensure both CUDA_VISIBLE_DEVICES and HIP_VISIBLE_DEVICES environment variables are set correctly when running on AMD/HIP hardware. This targeted bug fix improved cross-vendor compatibility and made device selection more reliable for CUDA workflows on non-NVIDIA devices. By aligning environment configuration with user expectations, the update reduced misconfiguration risks and contributed to a smoother onboarding process for users with diverse GPU setups.