Before applying the v8.1.1 update, it is highly recommended to create a full system dump using an Android terminal.
While official changelogs for these specific Chinese-market head units can be difficult to find, community discussions on platforms like the 4PDA forums suggest the following improvements in the v8.1.1 series: fota v8.1.1 %21NEW%21
Hardware and firmware for Allwinner T3 variants (like K2001 vs. T3L) are not compatible . Installing the wrong version can destroy the motherboard. Update Methods: Before applying the v8
Better support for USB ports and various multimedia formats. Before applying the v8.1.1 update