我正在按照标准过程使用SDcard来启动sama5d27-som1-ek套件，但出现以下错误
我不明白为什么它显示无法打开根设备。我为此过程使用了8GB SD。
VFS: Cannot open root device "mmcblk0p2" or unknown-block(179,2): error -30
Please append a correct "root=" boot option; here are the available partitions:
0100 8192 ram0
(driver?)
0101 8192 ram1
(driver?)
0102 8192 ram2
(driver?)
0103 8192 ram3
(driver?)
1f00 64 mtdblock0
(driver?)
1f01 640 mtdblock1
(driver?)
1f02 64 mtdblock2
(driver?)
1f03 128 mtdblock3
(driver?)
1f04 4096 mtdblock4
(driver?)
b300 7864320 mmcblk0
driver: mmcblk
b301 65536 mmcblk0p1 da6e5492-01
b302 914432 mmcblk0p2 da6e5492-02
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,2)
CPU: 0 PID: 1 Comm: swapper Not tainted 4.19.78-linux4sam-6.2 #1
Hardware name: Atmel SAMA5
Function entered at [<c010dcd8>] from [<c010ae5c>]
Function entered at [<c010ae5c>] from [<c0117f48>]
Function entered at [<c0117f48>] from [<c0a01270>]
Function entered at [<c0a01270>] from [<c0a01590>]
Function entered at [<c0a01590>] from [<c0a01730>]
Function entered at [<c0a01730>] from [<c0a00e1c>]
Function entered at [<c0a00e1c>] from [<c0729e00>]
Function entered at [<c0729e00>] from [<c01010e8>]
Exception stack(0xc642dfb0 to 0xc642dff8)
dfa0: 00000000 00000000 00000000 00000000
dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
dfe0: 00000000 00000000 00000000 00000000 00000013 00000000
---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,2) ]---
random: fast init done
random: crng init done
请帮助了解错误。因为我正在遵循标准流程。