Specifications

Image Name: Linux-2.4.25
Image Type: PowerPC Linux Kernel Image (gzip compressed)
Data Size: 1003065 Bytes = 979.6 kB
Load Address: 00000000
Entry Point: 00000000
Verifying Checksum ... OK
Uncompressing Kernel Image ... Error: inflate() returned -3
GUNZIP ERROR - must RESET board to recover
Answer:
Your kernel image is quite big - nearly 1 MB compressed; when it gets uncompressed it will need 2.5
... 3 MB, starting at address 0x0000. But your compressed image was stored at 1 MB (0x100000), so
the uncompressed code will overwrite the (remaining) compressed image. The solution is thus simple:
just use a higher address to download the compressed image into RAM. For example, try:
=> bootm 400000
14.3.3. Linux Post Mortem Analysis
You may find yourself in a situation where the Linux kernel crashes or hangs without any output on the
console. The first attempt to get more information in such a situation is a Post Mortem dump of the log buffer
- often the Linux kernel has already collected useful information in its console I/O buffer which just does not
get printed because the kernel does not run until successful initialization of the console port.
Proceed as follows:
Find out the virtual address of the log buffer; For 2.4 Linux kernels search for "log_buf":
2.4 Linux:
bash$ grep log_buf System.map
c0182f54 b log_buf
Here the virtual address of the buffer is 0xC0182F54
For 2.6 kernels "__log_buf" must be used:
bash$ grep __log_buf System.map
c02124c4 b __log_buf
Here the virtual address of the buffer is 0xC02124C4
1.
Convert to physical address: on Power Architecture® systems, the kernel is usually configured for a
virtual address of kernel base (CONFIG_KERNEL_START) of 0xC0000000. Just subtract this value
from the address you found. In our case we get:
physical address = 0xC0182F54 - 0xC0000000 = 0x00182F54
2.
Reset your board - do not power-cycle it!3.
Use your boot loader (you're running U-Boot, right?) to print a memory dump of that memory area:
=> md 0x00182F54
4.
This whole operation is based on the assumption that your boot loader does not overwrite the RAM contents -
U-Boot will take care not to destroy such valuable information.
14.3.3. Linux Post Mortem Analysis 175