Methods and apparatus to extend local buffer of a hardware accelerator are disclosed herein. In some examples, an apparatus, including a local memory, a first hardware accelerator (HWA), a second HWA, the second HWA and the first HWA connected in a flexible data pipeline, and a spare scheduler to manage, in response to the spare scheduler inserted in the flexible data pipeline, data movement between the first HWA and the second HWA through the local memory and a memory. Local buffer extension may be performed by software to control data movement between local memory and other system memory. The other system memory may be on-chip memory and/or external memory. The HWA sub-system includes a set of spare schedulers to manage the data movement. Data aggregation may be performed in the other system memory. Additionally, the other system memory may be utilized for conversion between data line and data block.