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I'm trying to debug an embedded device, connection via serial port, connected with USB to UART cable. Embedded Linux v.2.6.26.5 How to access the root filesystem "/" and subdirectories under the root FS? The shell command is not available in U-boot mode. Is there a way to access shell CLI from U-boot? The available U-boot commands and logs is here and here.

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I guess you need to Follow the Third stage of U-boot.

The third stage is the loading of the Linux kernel. However, before the Linux kernel takes control, u-boot passes a command line to the kernel containing essential parameters. These parameters can be viewed after the operating system has booted by typing the following into a Terminal window:

$ cat /proc/cmdline
root=/dev/mmcblk0p2 rootwait rw console=ttyS0,115200n8 console=tty0 no_console_suspend vdaccfg=0xa000 logo=osd1,loaded,0x7900000,720p,full dmfc=3 cvbsmode=576cvbs hdmimode=1080p m_bpp=32 vout=hdmi disablehpd=true

The kernel initializes the hardware, mounts the root filesystem (according to the root=... kernel parameter) and passes the control flow to /sbin/init. if you need more details abt Uboot Follow this link

  • You mean I need wait until the Linux kernel fully loaded (stage 3 of U-boot), not interrupt the automatic boot process? – minto Apr 10 '17 at 10:31
  • follow the link i gave below the stage 3 there is Disk layout and partitioning and u-boot environment setup . which ll help you setup ur / partition. – Vinood NK Maheshwari Apr 10 '17 at 10:48

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