2008-03-25 07:05:11 access to the u-boot environment
Thomas Sauter (GERMANY)
Message: 53007 Hello,
I build the u-boot-tools.
I try to read the environment in MTD-Flash, but:
Warning: Bad CRC, using default environment.
The Device offset, Env. size and Flash sector size settings in the config-file are correct.
how can I access and change the u-Boot env variables in u-Clinux?
Thanks
Thomas
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2008-03-25 08:16:31 Re: access to the u-boot environment
Mike Frysinger (UNITED STATES)
Message: 53012 you use the u-boot-tools to easily access the environment variables ... or you read/write the sectors yourself
did you create /etc/fw_env.config with the correct values ?
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2008-03-25 09:01:06 Re: access to the u-boot environment
Thomas Sauter (GERMANY)
Message: 53016 Here my fw_env.config:
# MTD device name Device offset Env. size Flash sector size
/dev/mtd0 0x0000 0x4000 0x4000
I have an seperat partition for u-boot on serial flash m25P128.:
/dev/mtd0
dev: size erasesize name
mtd0: 00040000 00040000 "Bootloader_Sector_0"
Here the output from fw_printenv:
root:/tmp> ./fw_printenv
Warning: Bad CRC, using default environment
bootcmd=bootp; setenv bootargs root=/dev/nfs nfsroot=${serverip}:${rootpath} ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}::off; bootm
bootdelay=5
baudrate=115200
With dd I can read the env-variables:
dd if=/dev/mtd0 of=/tmp/bla.txt skip=32 count=1
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2008-03-25 10:28:13 Re: access to the u-boot environment
Robin Getz (UNITED STATES)
Message: 53017 Thomas:
What version of U-Boot are you using? Are you using the default U-Boot, or did you type "save" at a U-Boot prompt, and then boot to a kernel? (I thought there was an issue with the default CRC32 being caclulated incorrect on 64-bit hosts on old versions of U-Boot).
-robin
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2008-03-26 00:44:44 Re: access to the u-boot environment
Mike Frysinger (UNITED STATES)
Message: 53028 if /dev/mtd0 represents all of u-boot, then an offset of '0x0000' clearly wont work as that is the start of u-boot, not the start of the environment
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2008-03-26 04:54:12 Re: access to the u-boot environment
Thomas Sauter (GERMANY)
Message: 53040 Robin:
u-boot version is 1.1.6.
I can change, add, delete and save the env-variables in u-boot.
I have added some new env variables.
After reset , no crc-error at u-boot prompt.
Mike:
I have copy u-boot to flash-position 0x0 .
/dev/mtd0 size is 0x40000 (256 blocks) and starts on 0x0.
This is the dd (skip=0) output, read with hexdump:
...
00001e40 48 e1 fd 03 08 e1 60 87 08 98 18 58 40 43 20 32 |H.....`....X@C 2|
00001e50 fa 67 82 c6 c3 83 02 0c a0 5e 10 91 c1 58 f5 17 |.g.......^...X..|
00001e60 01 e8 00 00 03 30 84 04 10 00 00 00 00 00 00 00 |.....0..........|
00001e70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00004160 00 00 00 00 00 00 00 00 00 00 00 00 00 00 29 59 |..............)Y|
00004170 dd 73 62 6f 6f 74 63 6d 64 3d 72 75 6e 20 66 6c |.sbootcmd=run fl|
00004180 61 73 68 62 6f 6f 74 00 62 6f 6f 74 64 65 6c 61 |ashboot.bootdela|
00004190 79 3d 35 00 62 61 75 64 72 61 74 65 3d 35 37 36 |y=5.baudrate=576|
000041a0 30 30 00 6c 6f 61 64 73 5f 65 63 68 6f 3d 31 00 |00.loads_echo=1.|
000041b0 61 75 74 6f 6c 6f 61 64 3d 6e 6f 00 72 6f 6f 74 |autoload=no.root|
000041c0 70 61 74 68 3d 2f 72 6f 6d 66 73 00 68 6f 73 74 |path=/romfs.host|
000041d0 6e 61 6d 65 3d 42 43 4f 4d 00 6c 6f 61 64 61 64 |name=BCOM.loadad|
.
.
.
00004770 61 64 64 72 3d 31 30 2e 31 30 2e 35 31 2e 32 32 |addr=10.10.51.22|
00004780 33 00 73 65 72 76 65 72 69 70 3d 31 30 2e 31 30 |3.serverip=10.10|
00004790 2e 35 31 2e 32 32 39 00 6b 65 72 6e 65 6c 73 69 |.51.229.kernelsi|
000047a0 7a 65 3d 30 78 64 65 65 64 62 00 00 00 00 00 00 |ze=0xdeedb......|
000047b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
...
I think, the env-Variables starts on 0x4160 and ends on 0x47b0?
What are the correct setting in fw_env.config?
Device offset= ?
Env.size= ?
Flash sector size=0x40000 (m25P128)
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2008-03-26 10:34:11 Re: access to the u-boot environment
Mike Frysinger (UNITED STATES)
Message: 53058 well, the exact flash offset value should be known to you considering you configured and compiled u-boot
rather than poking at the raw stream and trying to guess the offset, just consult your board configuration file