The first thing that I want to do today is to unbrick my NCB3AST. To unbrick it, I need to have a RS232 TTL converter. After waking up late, and doing some other weekend business, I went to Icon in Chiang Mai. I bought a data cable for Alcatel 511 (actually almost any data cable that isn’t mini USB would be fine, this is the one that I found), and after looking around, I found the schematics for the data cable. It helps me to decide where should I connect each cable guided by the close up photo from Chris.
I still doesn’t understand why my new image won’t boot, it always stops with:
pc : [<00500004>] lr : [<0d05ae60>]
sp : 0d05af00 ip : 00500000 fp : 0cf00000
r10: e8bd0070 r9 : 00000000 r8 : 00000108
r7 : 00613226 r6 : 00900000 r5 : 54420005 r4 : 00000004
r3 : 0cf00000 r2 : 0003a530 r1 : 00000001 r0 : 0003a7d4
Flags: nZcv IRQs off FIQs off Mode SVC_32
The default boot command is
cp.l 0x10020000 0xcf00000 0x1f0000;go cf00000
After quite a long time, I realized that if i just type:
The kernel will be loaded just fine. I don’t understand why the firmware won’t work when the kernel is copied to cf00000 and then booted. If i have a debugger, then this memory debugging stuff can be much easier to solve.
After the device can be booted, I decided to reflash it with the original firmware. I spent most of the time after that to:
- Learn about armboot (I will write about this tomorrow).
- Setup tftp server (atftpd, advanced tftpd) on my WRT54GL
- Build and compile the Linux kernel from WRVS440N
- Learn to load kernel from tftp
The results are:
- I understand most of armboot’s command
- I have a tftp server up and running
- I can configure and compile 2.4.27 kernel
- I can boot the kernel for star 9109. Everything seems to be working fine (except the network interface, it was detected, but I can’t connect to anywhere, but I need to check further).
I still haven’t been able to create completely new firmware. My next plan is:
- To compile a completely new kernel, and merge it with existing initrd
- Modify initrd so I can add new stuff
On the next posts I will write more instruction on how to connect to serial port and to use armboot.