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预计阅读 15 分钟U-Boot 下读写 UBI 方法
1. 依赖的环境变量
U-Boot 的 mtdparts 命令依赖两个环境变量：
1. mtdids：U-Boot 设备名 <-> Linux MTD 名的映射
2. mtdparts：分区表定义
注意：
•
mtdids=nand0:nand不是这里使用的格式•
mtdparts=mtdparts=nand:...可用
2. 操作步骤
2.1 修正 mtdids
| setenv mtdids nand0=nand |
| printenv mtdids |
| # 期望看到：mtdids=nand0=nand |
2.2 设置 mtdparts（你的板子分区）
| setenv mtdparts 'mtdparts=nand:1M(boot),8M(kernel),40M(rootfs),-(data)' |
| printenv mtdparts |
| # 期望看到：mtdparts=mtdparts=nand:1M(boot),8M(kernel),40M(rootfs),-(data) |
2.3 解析并展示分区表
| mtdparts |
预期：看到 nand0 下 4 个分区：boot / kernel / rootfs / data。
2.4 清空 data 分区并初始化为 UBI
危险：会擦除
data分区
| nand erase.part data |
| ubi part data |
| ubi info |
2.5 创建卷并做读写验证
| ubi create datavol 0x1400000 d |
| ubi info l |
| ubi write 0x82000000 datavol 0x100000 |
| ubi read 0x83000000 datavol 0x100000 |
| md.b 0x83000000 0x40 |
2.6 持久化（确认没问题后再保存）
| saveenv |
3. 快速自测（固定字节）
| # 往 0x82000000 填充 0x5A，共 0x1000 字节 |
| mw.b 0x82000000 0x5A 0x1000 |
| # 写入卷 |
| ubi write 0x82000000 datavol 0x1000 |
| # 读回到 0x83000000 |
| ubi read 0x83000000 datavol 0x1000 |
| # 检查前 64 字节应基本都是 5A |
| md.b 0x83000000 0x40 |
4. 实测日志
| x2000_halley5# printenv mtdids |
| mtdids=nand0:nand |
| x2000_halley5# printenv mtdparts |
| mtdparts=mtdparts=nand:1M(boot),8M(kernel),40M(rootfs),-(data) |
| x2000_halley5# |
| setenv mtdids nand0=nand |
| x2000_halley5# setenv mtdparts 'mtdparts=nand:1M(boot),8M(kernel),40M(rootfs),-(data)' |
| x2000_halley5# mtdparts |
| device nand0 <nand>, # parts = 4 |
| #: name size offset mask_flags |
| 0: boot 0x00100000 0x00000000 0 |
| 1: kernel 0x00800000 0x00100000 0 |
| 2: rootfs 0x02800000 0x00900000 0 |
| 3: data 0x04f00000 0x03100000 0 |
| active partition: nand0,0 - (boot) 0x00100000 @ 0x00000000 |
| defaults: |
| mtdids : nand0:nand |
| mtdparts: mtdparts=nand:1M(boot),8M(kernel),40M(rootfs),-(data) |
| x2000_halley5# nand erase.part data |
| NAND erase.part: device 0 offset 0x3100000, size 0x4f00000 |
| Erasing at 0x7fe0000 -- 100% complete. |
| OK |
| x2000_halley5# |
| x2000_halley5# ubi part data |
| UBI: attaching mtd1 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: empty MTD device detected |
| UBI: create volume table (copy #1) |
| UBI: create volume table (copy #2) |
| UBI: attached mtd1 to ubi0 |
| UBI: MTD device name: "mtd=3" |
| UBI: MTD device size: 79 MiB |
| UBI: number of good PEBs: 632 |
| UBI: number of bad PEBs: 0 |
| UBI: max. allowed volumes: 128 |
| UBI: wear-leveling threshold: 4096 |
| UBI: number of internal volumes: 1 |
| UBI: number of user volumes: 0 |
| UBI: available PEBs: 616 |
| UBI: total number of reserved PEBs: 16 |
| UBI: number of PEBs reserved for bad PEB handling: 12 |
| UBI: max/mean erase counter: 1/0 |
| x2000_halley5# ubi info |
| UBI: MTD device name: "mtd=3" |
| UBI: MTD device size: 79 MiB |
| UBI: physical eraseblock size: 131072 bytes (128 KiB) |
| UBI: logical eraseblock size: 126976 bytes |
| UBI: number of good PEBs: 632 |
| UBI: number of bad PEBs: 0 |
| UBI: smallest flash I/O unit: 2048 |
| UBI: VID header offset: 2048 (aligned 2048) |
| UBI: data offset: 4096 |
| UBI: max. allowed volumes: 128 |
| UBI: wear-leveling threshold: 4096 |
| UBI: number of internal volumes: 1 |
| UBI: number of user volumes: 0 |
| UBI: available PEBs: 616 |
| UBI: total number of reserved PEBs: 16 |
| UBI: number of PEBs reserved for bad PEB handling: 12 |
| UBI: max/mean erase counter: 1/0 |
| x2000_halley5# |
| x2000_halley5# ubi create datavol 0x1400000 d |
| Creating dynamic volume datavol of size 20971520 |
| x2000_halley5# ubi info l |
| UBI: volume information dump: |
| UBI: vol_id 0 |
| UBI: reserved_pebs 166 |
| UBI: alignment 1 |
| UBI: data_pad 0 |
| UBI: vol_type 3 |
| UBI: name_len 7 |
| UBI: usable_leb_size 126976 |
| UBI: used_ebs 166 |
| UBI: used_bytes 21078016 |
| UBI: last_eb_bytes 126976 |
| UBI: corrupted 0 |
| UBI: upd_marker 0 |
| UBI: name datavol |
| UBI: volume information dump: |
| UBI: vol_id 2147479551 |
| UBI: reserved_pebs 2 |
| UBI: alignment 1 |
| UBI: data_pad 0 |
| UBI: vol_type 3 |
| UBI: name_len 13 |
| UBI: usable_leb_size 126976 |
| UBI: used_ebs 2 |
| UBI: used_bytes 253952 |
| UBI: last_eb_bytes 2 |
| UBI: corrupted 0 |
| UBI: upd_marker 0 |
| UBI: name layout volume |
| x2000_halley5# ubi write 0x82000000 datavol 0x100000 |
| 1048576 bytes written to volume datavol |
| x2000_halley5# ubi read 0x83000000 datavol 0x100000 |
| Read 1048576 bytes from volume datavol to 83000000 |
| x2000_halley5# md.b 0x83000000 0x40 |
| 83000000: 55 42 49 23 01 00 00 00 00 00 00 00 00 00 00 04 UBI#............ |
| 83000010: 00 00 08 00 00 00 10 00 00 00 00 00 00 00 00 00 ................ |
| 83000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ |
| 83000030: 00 00 00 00 00 00 00 00 00 00 00 00 3f 05 d0 a6 ............?... |
| x2000_halley5# ubi write 0x82000000 datavol 0x100000 |
| 1048576 bytes written to volume datavol |
| x2000_halley5# ubi read 0x83000000 datavol 0x100000 |
| Read 1048576 bytes from volume datavol to 83000000 |
| x2000_halley5# md.b 0x83000000 0x40 |
| 83000000: 55 42 49 23 01 00 00 00 00 00 00 00 00 00 00 04 UBI#............ |
| 83000010: 00 00 08 00 00 00 10 00 00 00 00 00 00 00 00 00 ................ |
| 83000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ |
| 83000030: 00 00 00 00 00 00 00 00 00 00 00 00 3f 05 d0 a6 ............?... |
| x2000_halley5# |
| x2000_halley5# mw.b 0x82000000 0x5A 0x1000 |
| x2000_halley5# ubi write 0x82000000 datavol 0x1000 |
| 4096 bytes written to volume datavol |
| x2000_halley5# ubi read 0x83000000 datavol 0x1000 |
| Read 4096 bytes from volume datavol to 83000000 |
| x2000_halley5# md.b 0x83000000 0x40 |
| 83000000: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ |
| 83000010: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ |
| 83000020: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ |
| 83000030: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ |
| x2000_halley5# |