The stock BL2 and FIP of JDCloud RE-CP-03 were builted WITH secure boot, we should build and replace them together. Only replacing FIP will cause bricks.
But The stock BL2 and FIP of CMCC RAX3000M eMMC were builded WITHOUT secure boot, we only need to build and replace FIP.
The single boot gpt of JDCloud RE-CP-03 and CMCC RAX3000M eMMC is like that:
Device
Start
End
Sectors
Size
Name
/dev/mmcblk0p1
8192
9215
1024
512K
u-boot-env
/dev/mmcblk0p2
9216
13311
4096
2M
factory
/dev/mmcblk0p3
13312
17407
4096
2M
FIP
/dev/mmcblk0p4
17408
50175
32768
16M
kernel
/dev/mmcblk0p5
50176
1098751
1048576
512M
rootfs
We can see the u-boot-env offset is 8192 sectors * 512 bytes per sector = 4194304 bytes = 0x400000 bytes.
The stock BL2 and FIP of JDCloud RE-CP-03 were builted WITH secure boot, we should build and replace them together. Only replacing FIP will cause bricks.
But The stock BL2 and FIP of CMCC RAX3000M eMMC were builded WITHOUT secure boot, we only need to build and replace FIP.
We can see the u-boot-env offset is 8192 sectors * 512 bytes per sector = 4194304 bytes = 0x400000 bytes.