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Table of Contents
Android Partitions on MTK Devices
NAND Flash vs eMMC Flash
NAND flash can only be read in pages, some bits in a page may be wrong and need to be corrected by an error correction mechanism. With NAND flash the OS and device drivers are responsible to handle these issues.
eMMC Flash combines NAND memory with a built-in controller, that handles most of the things you have to take care of when dealing with NAND flash.
EMMC Regions
EMMC_BOOT_1 and EMMC_USER
Inspecting partitions on the command line
The following commands were executed on a ZTE Blade A610, running Android 6.0, via the adb shell command line. The phone was rooted so that the su command was available.
cat /proc/partitions
cat /proc/partitions major minor #blocks name 7 0 12910 loop0 254 0 986264 zram0 179 0 15388672 mmcblk0 179 1 3072 mmcblk0p1 179 2 5120 mmcblk0p2 179 3 10240 mmcblk0p3 179 4 10240 mmcblk0p4 179 5 512 mmcblk0p5 179 6 512 mmcblk0p6 179 7 16384 mmcblk0p7 179 8 16384 mmcblk0p8 179 9 8192 mmcblk0p9 179 10 10240 mmcblk0p10 179 11 512 mmcblk0p11 179 12 2048 mmcblk0p12 179 13 6144 mmcblk0p13 179 14 8192 mmcblk0p14 179 15 5120 mmcblk0p15 179 16 5120 mmcblk0p16 179 17 1024 mmcblk0p17 179 18 32768 mmcblk0p18 179 19 37888 mmcblk0p19 179 20 3022848 mmcblk0p20 179 21 409600 mmcblk0p21 179 22 11759104 mmcblk0p22 179 23 16384 mmcblk0p23 179 96 4096 mmcblk0rpmb 179 64 4096 mmcblk0boot1 179 32 4096 mmcblk0boot0 253 0 11759104 dm-0
sgdisk
The /system/bin/sgdisk command is accessible only with root privileges.
sgdisk --print /dev/block/mmcblk0 < Disk /dev/block/mmcblk0: 30777344 sectors, 14.7 GiB Logical sector size: 512 bytes Disk identifier (GUID): 00000000-0000-0000-0000-000000000000 Partition table holds up to 23 entries First usable sector is 1024, last usable sector is 30776319 Partitions will be aligned on 1024-sector boundaries Total free space is 0 sectors (0 bytes) Number Start (sector) End (sector) Size Code Name 1 1024 7167 3.0 MiB 0700 proinfo 2 7168 17407 5.0 MiB 0700 nvram 3 17408 37887 10.0 MiB 0700 protect1 4 37888 58367 10.0 MiB 0700 protect2 5 58368 59391 512.0 KiB 0700 lk 6 59392 60415 512.0 KiB 0700 para 7 60416 93183 16.0 MiB 0700 boot 8 93184 125951 16.0 MiB 0700 recovery 9 125952 142335 8.0 MiB 0700 logo 10 142336 162815 10.0 MiB 0700 expdb 11 162816 163839 512.0 KiB 0700 seccfg 12 163840 167935 2.0 MiB 0700 oemkeystore 13 167936 180223 6.0 MiB 0700 secro 14 180224 196607 8.0 MiB 0700 keystore 15 196608 206847 5.0 MiB 0700 tee1 16 206848 217087 5.0 MiB 0700 tee2 17 217088 219135 1024.0 KiB 0700 frp 18 219136 284671 32.0 MiB 0700 nvdata 19 284672 360447 37.0 MiB 0700 metadata 20 360448 6406143 2.9 GiB 0700 system 21 6406144 7225343 400.0 MiB 0700 cache 22 7225344 30743551 11.2 GiB 0700 userdata 23 30743552 30776319 16.0 MiB 0700 flashinfo
/dev/block/mmcblk0boot0
The partition /dev/block/mmcblk0boot0 is the one referred as region EMMC_BOOT_1 in the scatter file, dedicated to the preloader.
The actual Linux device content starts with the characters EMMC_BOOT. It seems that it is an header of 2048 (0x800) bytes and the actual preloader follows that header. 
Some stock ROMs include the preloader image, without that header. But if you readback the preloader partition using SP Flash Tool, you get an image with that heder included.