重新格式化 SD 卡

我需要將 SD 卡重新格式化回出廠狀態。

用於媒體的 SD 卡文件系統已損壞。訪問某個目錄會導致文件系統以只讀方式重新掛載，並且無法刪除。fsck.vfat 說它沒有針對特定類型的損壞的修復方法。

提醒：像這樣的命令旨在覆蓋文件系統數據。您必須格外小心，以免瞄準錯誤的磁碟。

編輯：

在格式化卡之前，您可能還需要執行丟棄操作。

blkdiscard /dev/mmcblk0

這可能會提高性能 - 與 SATA SSD 上的 TRIM 相同。從理論上講，重置塊重映射層也可能有助於解決該層或其周圍的損壞，儘管此方法不如專用的完整設備擦除命令（SATA 安全擦除）。並非所有讀卡器都支持此功能。在我的戴爾 Latitude 筆記型電腦上，它在一秒鐘內將卡重置為全零。這意味著在這張卡上它只影響了塊重映射層；它不能立即擦除整個 16GB 快閃記憶體。

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MicroSD 卡包含一個或多個快閃記憶體晶片和一個小型微處理器，充當 SD 卡規範和快閃記憶體晶片之間的介面。卡通常在工廠進行格式化以獲得接近最佳的性能。但是，大多數作業系統預設的分區和格式化實用程序將卡視為傳統硬碟驅動器。適用於傳統硬碟驅動器的方法會降低基於快閃記憶體的卡的性能和使用壽命

http://3gfp.com/wp/2014/07/formatting-sd-cards-for-speed-and-lifetime/

腳本可用於高達 32GiB 的卡。我已對其進行了修改以適用於目前版本的sfdisk. 在生成的分區上執行file -s返回與以前相同的數字，除了每個磁軌的磁頭/扇區數。目前作業系統不使用這些，儘管顯然某些嵌入式引導載入程序需要特定值。

#! /bin/sh
# fdisk portion of script based on mkcard.sh v0.4
# (c) Copyright 2009 Graeme Gregory <dp@xora.org.uk>
# Additional functionality by Steve Sakoman
# (c) Copyright 2010-2011 Steve Sakoman <steve@sakoman.com>
# Updated by Alan Jenkins (2016)
# Licensed under terms of GPLv2
#
# Parts of the procudure base on the work of Denys Dmytriyenko
# http://wiki.omap.com/index.php/MMC_Boot_Format

# exit if any command fails
set -e

export LC_ALL=C

format_whole_disk_fat32() {
   if ! id | grep -q root; then
       echo "This utility must be run prefixed with sudo or as root"
       return 1
   fi

   local DRIVE=$1

   # Make sure drive isn't mounted    
   # so hopefully this will fail e.g. if we're about to blow away the root filesystem
   for mounted in $(findmnt -o source | grep "^$DRIVE") ; do
       umount "$mounted"
   done    

   # Make sure current partition table is deleted
   wipefs --all $DRIVE

   # Get disk size in bytes
   local SIZE=$(fdisk -l $DRIVE | grep Disk | grep bytes | awk '{print $5}')
   echo DISK SIZE – $SIZE bytes

   # Note: I'm changing our default cluster size to 32KiB since all of
   # our 8GiB cards are arriving with 32KiB clusters. The manufacturers
   # may know something that we do not *or* they're trading speed for
   # more space.
   local CLUSTER_SIZE_KB=32
   local CLUSTER_SIZE_IN_SECTORS=$(( $CLUSTER_SIZE_KB * 2 ))

   # This won't work for drives bigger than 32GiB because
   # 32GiB / 64kiB clusters = 524288 FAT entries
   # 524288 FAT entries * 4 bytes / FAT = 2097152 bytes
   # 2097152 bytes / 512 bytes = 4096 sectors for FAT size
   # 4096 * 2 = 8192 sectors for both FAT tables which leaves no
   # room for the BPB sector
   if [ $SIZE -ge $(( ($CLUSTER_SIZE_KB / 2) * 1024 * 1024 * 1024 )) ]; then
       echo -n "This drive is too large, >= $(($CLUSTER_SIZE_KB / 2))GiB, for this "
       echo "formatting routine."
       return 1
   fi

   # Align partitions for SD card performance/wear optimization
   # Summary: start 1st partition at sector 8192 (4MiB) and align FAT32
   #          data to start at 8MiB (4MiB logical)
   #          There's a document that explains why, but its too long to
   #          reproduce here.
   {
   echo 8192,,0x0C,*
   } | sfdisk -uS -q $DRIVE

   sleep 1

   if [ -b ${DRIVE}1 ]; then
       PART1=${DRIVE}1
   elif [ -b ${DRIVE}p1 ]; then
       PART1=${DRIVE}p1
   else
       echo "Improper partitioning on $DRIVE"
       return 1
   fi

   # Delete any old filesystem visible in new partition
   wipefs --all $PART1

   # Format FAT32 with 64kiB clusters (128 * 512)
   # Format once to get the calculated FAT size
   local FAT_SIZE=$(mkdosfs -F 32 -s $CLUSTER_SIZE_IN_SECTORS -v ${PART1} | \
       sed -n -r -e '/^FAT size is/ s,FAT size is ([0-9]+) sectors.*$,\1,p')

   # Calculate the number of reserved sectors to pad in order to align
   # the FAT32 data area to 4MiB
   local RESERVED_SECTORS=$(( 8192 - 2 * $FAT_SIZE ))

   # Format again with padding
   mkdosfs -F 32 -s $CLUSTER_SIZE_IN_SECTORS -v -R $RESERVED_SECTORS ${PART1}

   # Uncomment to label filesystem
   #fatlabel ${PART1} BOOT
}

#set -x

format_whole_disk_fat32 "$@"

引用自：https://unix.stackexchange.com/questions/312395