rootfs.ubiはログインシェルを許可しません。

buildroot 2012.11を使用してrootfs.ubiを構築しました。また、起動時にbuildrootログインプロンプトにログインすることはできません。 Linux は UBI と UBIFS サポートで構築されました。以前は、いくつかの問題が原因でrootfsが読み取り専用としてマウントされていた場合、この現象が発生しましたが、ログには読み取り専用は記載されておらず、読み取り専用のように動作します。

誰でもこの問題を解決するように指示できますか？

関連するログ行は次のとおりです。

Starting kernel ...

Booting Linux on physical CPU 0
Linux version 3.6.9 (root@hpro-wc-vm) (gcc version 4.6.3 (Sourcery CodeBench Lite 2012.03-57) ) #3 PREEMPT Fri Jun 24 17:14:18 IST 2016
Machine: Atmel SAMA5 (Device Tree), model: Atmel SAMA5D31-EK
AT91: Detected soc type: sama5d3
AT91: Detected soc subtype: sama5d31
AT91: sram at 0x300000 of 0x20000 mapped at 0xfef58000
Kernel command line: console=ttyS0,115200 earlyprintk mtdparts=atmel_nand:128k(img_selector),128k(uboot_env),128K(dtb_prim),128K(dtb_sec),2M(kernel_prim),2M(kernel_sec),40M(rootfs_prim),40M(rootfs_sec),-(user_data) ubi.mtd=7 root=ubi0_0 rw rootfstype=ubifs

...

9 cmdlinepart partitions found on MTD device atmel_nand
Creating 9 MTD partitions on "atmel_nand":
0x000000000000-0x000000020000 : "img_selector"
0x000000020000-0x000000040000 : "uboot_env"
0x000000040000-0x000000060000 : "dtb_prim"
0x000000060000-0x000000080000 : "dtb_sec"
0x000000080000-0x000000280000 : "kernel_prim"
0x000000280000-0x000000480000 : "kernel_sec"
0x000000480000-0x000002c80000 : "rootfs_prim"
0x000002c80000-0x000005480000 : "rootfs_sec"
0x000005480000-0x000008000000 : "user_data"
UBI: attaching mtd7 to ubi0
UBI: physical eraseblock size:   131072 bytes (128 KiB)
UBI: logical eraseblock size:    126976 bytes
UBI: smallest flash I/O unit:    2048
UBI: VID header offset:          2048 (aligned 2048)
UBI: data offset:                4096
UBI: max. sequence number:       0
UBI: volume 0 ("rootfs") re-sized from 106 to 310 LEBs
UBI: attached mtd7 to ubi0
UBI: MTD device name:            "rootfs_sec"
UBI: MTD device size:            40 MiB
UBI: number of good PEBs:        320
UBI: number of bad PEBs:         0
UBI: number of corrupted PEBs:   0
UBI: max. allowed volumes:       128
UBI: wear-leveling threshold:    4096
UBI: number of internal volumes: 1
UBI: number of user volumes:     1
UBI: available PEBs:             0
UBI: total number of reserved PEBs: 320
UBI: number of PEBs reserved for bad PEB handling: 6
UBI: max/mean erase counter: 1/1
UBI: image sequence number:  1458400647
UBI: background thread "ubi_bgt0d" started, PID 306
atmel_spi f0004000.spi: Using dma0chan1 (tx) and  dma0chan2 (rx) for DMA transfers
atmel_spi f0004000.spi: Atmel SPI Controller at 0xf0004000 (irq 18)
atmel_spi f0004000.spi: master is unqueued, this is deprecated
atmel_spi f8008000.spi: Using dma1chan0 (tx) and  dma1chan1 (rx) for DMA transfers
atmel_spi f8008000.spi: Atmel SPI Controller at 0xf8008000 (irq 26)
atmel_spi f8008000.spi: master is unqueued, this is deprecated
libphy: MACB_mii_bus: probed
macb f802c000.ethernet: eth0: Cadence MACB at 0xf802c000 irq 30 (00:0f:d4:06:d9:aa)
macb f802c000.ethernet: eth0: attached PHY driver [Generic PHY]         (mii_bus:phy_addr=f802c000.etherne:00, irq=-1)
at91_rtc fffffeb0.rtc: rtc core: registered fffffeb0.rtc as rtc0
AT91 Real Time Clock driver.
i2c /dev entries driver
TCP: cubic registered
NET: Registered protocol family 17
VFP support v0.3: implementor 41 architecture 2 part 30 variant 5 rev 1
at91_rtc fffffeb0.rtc: setting system clock to 2007-01-01 04:47:01 UTC (1167626821)
UBIFS: mounted UBI device 0, volume 0, name "rootfs"
UBIFS: file system size:   37965824 bytes (37076 KiB, 36 MiB, 299 LEBs)
UBIFS: journal size:       9023488 bytes (8812 KiB, 8 MiB, 72 LEBs)
UBIFS: media format:       w4/r0 (latest is w4/r0)
UBIFS: default compressor: lzo
UBIFS: reserved for root:  0 bytes (0 KiB)
VFS: Mounted root (ubifs filesystem) on device 0:10.
devtmpfs: mounted

...

grep: /proc/cmdline: No such file or directory
grep: /proc/cmdline: No such file or directory

...

awk: /proc/devices: No such file or directory

追加情報が必要な場合はお知らせください。