Question

我在beagleboard black上写了一些mmc写的东西。

问题在于：

U-Boot# usb start
(Re)start USB...
USB0:   scanning bus 0 for devices... 1 USB Device(s) found
       scanning usb for storage devices... 1 Storage Device(s) found
U-Boot# fatload usb 0 ${loadaddr} ${rootfs_file}
reading rootfs.ext4
18742272 bytes read in 12384 ms (1.4 MiB/s)
U-Boot# mmc dev 1
switch to partitions #0, OK
mmc1(part 0) is current device
U-Boot# mmc part

Partition Map for MMC device 1  --   Partition Type: DOS

Part    Start Sector    Num Sectors     UUID            Type
  1     63              1028097         00000000-01     0c Boot
  2     1028160         1028160         00000000-02     83
  3     2056320         1686825         00000000-03     83
U-Boot# mmc dev 1 2
switch to partitions #2, OK
mmc1(part 2) is current device
U-Boot# mmc write $loadaddr 0x0 0x20000

MMC write: dev # 1, block # 0, count 131072 ... MMC: block number 0xffff exceeds max(0x800)
0 blocks written: ERROR

为什么？分区2应该是64MB

此外

U-Boot# mmc info
Device: OMAP SD/MMC
Manufacturer ID: fe
OEM: 14e
Name: MMC02
Tran Speed: 52000000
Rd Block Len: 512
MMC version 4.41
High Capacity: No
Capacity: 1 MiB <=== ??? WHY ???
Bus Width: 4-bit

感谢您的回复

佛瑞德

Answer 1

AFAIK＆＃34; mmc写＆＃34;对MMC设备执行原始写入。它不通过文件系统执行写入。没有＆＃34;写＆＃34;支持大多数文件系统访问命令。只有ext4似乎有＆＃34;写＆＃34;操作（但我没有亲自测试过这个）。

＆＃34; mmc写＆＃34;你执行的操作可能会覆盖MMC分区表。

u boot mmc写在beaglebone黑色上的问题

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