我按照资料上改了u-boot 和内核的设置，但系统启动时，仍然不能挂载，出现如下错误，问题在哪里？是我的文件系统不对吗？
1.316381] VFS: Cannot open root device "31:03" or unknown-block(31,3): error -19
[ 1.324087] Please append a correct "root=" boot option; here are the available partitions:
[ 1.332464] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,3)
[ 1.340810] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.0-g338e6aaa6-dirty #15
[ 1.348193] Hardware name: Allwinner sun8i Family
[ 1.352927] [<c010ecf4>] (unwind_backtrace) from [<c010b724>] (show_stack+0x10/0x14)
[ 1.360668] [<c010b724>] (show_stack) from [<c06c2970>] (dump_stack+0x84/0x98)
[ 1.367888] [<c06c2970>] (dump_stack) from [<c011e024>] (panic+0x110/0x2fc)
[ 1.374848] [<c011e024>] (panic) from [<c090136c>] (mount_block_root+0x1a0/0x288)
[ 1.382325] [<c090136c>] (mount_block_root) from [<c0901598>] (mount_root+0x144/0x160)
[ 1.390235] [<c0901598>] (mount_root) from [<c0901704>] (prepare_namespace+0x150/0x194)
[ 1.398234] [<c0901704>] (prepare_namespace) from [<c06daddc>] (kernel_init+0x8/0x10c)
[ 1.406146] [<c06daddc>] (kernel_init) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
[ 1.413704] Exception stack(0xc2835fb0 to 0xc2835ff8)
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