This post is for personal reminder~
Tools Used#
Process and Details#
Firmware Preparation#
When only working on the main core package, the files needed for the modification process are core, rofs2, and rofs3. For flashing, core, dcp, vpl, and signature.bin are required.
General Process#
1 - Unpack the core using NFECore, and unpack rofs2 and rofs3 using NFE. Convert rofs2 to rofs and then rofs3 to rofs, and replace all files. If DIY is needed, perform DIY first, and then calculate the size of the resulting rofs folder in hexadecimal (convert the size in decimal of the unit M to hexadecimal by multiplying it by 1024*1024). At this point, the size of the core package is determined.
2 - Open the core package with WinHex, find the first 5400EE, and the core starting address is 2F steps after 5. The following is the header area, only modify the core size, C drive starting address, and C drive size. Note that for official packages: C drive starting address + C drive size < end address, and the original size of the gap here should be retained. The red underline part below should also be adjusted accordingly, with the value being: C drive starting address - 1.
3 - Continue scrolling down in WinHex to find the first 5401170E, which is the start of the partition table until FFFFFFFF. To modify the partition table for the core: reverse the values, so if the actual values are 01 02 03 04, enter 04 03 02 01.
The partition table to be modified starts approximately after SOS+CORE on the right side, with the red box in the image indicating the starting address and the green box indicating the corresponding partition size. The first and last red boxes should not be modified, the core size should be filled in as mentioned above, and both rofs2 and rofs3 sizes should be 0, while the C drive size should also be filled in as mentioned above.
4 - The most important 0x54 segment verification, if not modified, the phone will not boot after flashing!
Method:
4.1 Open rofs2 with WinHex, from the beginning B2 to before the first 5D01272D, a very short segment. After selecting, right-click - Edit - Copy Block - To New File, name it jiaoyan, with the extension fpsx, or any other extension.
4.2 Go back to the modified core package, select the partition table part mentioned above, right-click - Edit - Copy Block - Hexadecimal values, and then paste it at the end of the jiaoyan file, save it, and do not exit WinHex.
4.3 Open jiaoyan.fpsx with nokiacooker, then immediately save and exit. Go back to WinHex and you will see that the jiaoyan file has changed. After refreshing, check the 2 changes after 5401170E, the changed values are within the red box in the image. Fill in the changed values in the partition table of the core package.
5 - Place the verified core package into NFECore, click on "rofs capacity adjustment" without any error to confirm success. Also, click on "verify modification", if all values are 2B, change them all to 2A. Make sure all the files in rofs are ready, then click on "pack" to obtain the flashing core package.