BCT
Boot Configuration Table
The boot configuration table contains information about which bootloader to boot. On the Surface RT it is stored on the SPI flash. Go to SPI flash, to dump it directly from SPI. Or do it with nvflash (recommended):
sudo ./utils/nvflash_v1.13.87205 --getbct --bct surfacert.bin --configfile ./utils/flash.cfg To decompile your BCT into a configuration file, use the tool bct_dump.
Usage:
bct_dump <your-bct-file>
Tip you can add > <output-file> to reroute the output to a file.You can compile your bct.cfg file by using the tool cbootimage.
Usage:
cbootimage -s tegra30 -t 30 -gbct <input-bct-configuration-file> <output-bct-file>
Example: cbootimage -s tegra30 -t 30 -gbct surfacert-custom.bct.cfg surfacert-custom.bctTo generate a image file with your BCT and provided bootloader, again use cbootimage.
Usage:
cbootimage -d -s tegra30 -t 30 <input-config-file> <output-image-file>
Example: cbootimage -d -s tegra30 -t 30 surfacert.config surfacert.output
<input-config-file> is a file controlling how the .img file should be created. It has the following structure:# Refernence: https://github.com/NVIDIA/cbootimage-configs/blob/master/tegra30/nvidia/cardhu/cardhu-a05-2gb-emmc.img.cfg
Version = 0x00000001;
Bctcopy = 1;
Bctfile = <your-bct-file>;
BootLoader = <bootloader-file-name>,<load-address>,<entry-point>,Complete;
Example:
Version = 0x00000001;
Bctcopy = 1;
Bctfile = surfacert-custom.bct;
BootLoader = mtd0-bootloader,0x80808000,0x80808000,Complete;
Doing this will create a image file of your BCT and the bootloader you provided. The BCT will automatically updated with the correct sizes and hashes.
Last modified 2yr ago