In case it helps, I got the flash layout from factory firmware:
MT7981> mmc part
Partition Map for MMC device 0-- Partition Type: EFI
Part Start LBA End LBA Name Attributes Type GUID Partition GUID
1 0x00000000 0x00000021 "gpt" attrs:0x0000000000000000 type:0fc63daf-8483-4772-8e79-3d69d8477de4 (linux) guid:d65a0088-db5c-11ee-a187-000c29358ede
2 0x00002000 0x000023ff "u-boot-env" attrs:0x0000000000000000 type:0fc63daf-8483-4772-8e79-3d69d8477de4 (linux) guid:19a4763a-6b19-4a4b-a0c4-8cc34f4c2ab9
3 0x00002400 0x000033ff "factory" attrs:0x0000000000000000 type:0fc63daf-8483-4772-8e79-3d69d8477de4 (linux) guid:8142c1b2-1697-41d9-b1bf-a88d76c7213f
4 0x00003400 0x000043ff "fip" attrs:0x0000000000000000 type:0fc63daf-8483-4772-8e79-3d69d8477de4 (linux) guid:18de6587-4f17-4e08-a6c9-d9d3d424f4c5
5 0x00004400 0x000143ff "kernel" attrs:0x0000000000000000 type:0fc63daf-8483-4772-8e79-3d69d8477de4 (linux) guid:971f7556-ef1a-44cd-8b28-0cf8100b9c7e
6 0x00014400 0x00e00000 "rootfs" attrs:0x0000000000000000 type:0fc63daf-8483-4772-8e79-3d69d8477de4 (linux) guid:309a3e76-270b-41b2-b5d5-ed8154e7542b
cat /proc/partitions
>major minor # blocks name
> 7 0 7285312 loop0
>179 0 7634944 mmcblk0
>179 1 17 mmcblk0p1
>179 2 512 mmcblk0p2
>179 3 2048 mmcblk0p3
>179 4 2048 mmcblk0p4
>179 5 32768 mmcblk0p5
>179 6 7298560 mmcblk0p6