Found on forums like 4PDA , this is a modified system.img based on the official Chinese firmware. It includes built-in root access via Kinguser and is "debloated" by removing unnecessary Huawei and Google apps to improve performance .
The primary roadblock is the tablet’s and Huawei's restrictive bootloader . The vast majority of the custom ROM community is built around devices with Qualcomm or MediaTek chips, leaving Spreadtrum (now Unisoc) devices in a niche with far less support. The Spreadtrum SC7731G is a Quad-core 1.2 GHz ARM Cortex-A7 processor, which, while capable of basic tasks, is not a priority for most ROM developers. huawei mediapad t1 70 custom rom top
Move beyond KitKat/Marshmallow to Android 7.0 or higher. Found on forums like 4PDA , this is a modified system