Just ran into the same problem and it seems to be that /dev/disk* is slow because it is buffered. If you use the corresponding rdisk device (ex: /dev/rdisk1s1) you should get the speed you expect. This is apparently a BSD thing.
% sudo dd if=pi.bin of=/dev/disk1 bs=1m count=4095
^C408+0 records in
407+0 records out
426770432 bytes transferred in ...
A better and simpler solution would be using the command-line.
Execute the following command to identify the mount name of SD card following the pattern /dev/diskX, e.g., /dev/disk2
Say the disk name is /dev/disk2. Now format the card to FAT32 by running the following command:
sudo diskutil eraseDisk FAT32 MYSD MBRFormat /dev/disk2
This thread says that there's a switch in the SD card slot that detects when a card is inserted, and it can get clogged by dust or jammed or something. If you play around with a toothpick (or anything that fits in that hole), it'll fix your problem. Toggling that switch helps.
The diskutil command on macOS is incredibly powerful and can do all that you need. (You can run the following in the Terminal app.)
Find your SD card:
$ diskutil list
$ diskutil list external physical
On the right, under IDENTIFIER, you'll see your disk labeled like disk2 or disk3, etc. You can use that label to reference your SD card from now on....
Do you happen to have the Android File Transfer application installed? Various users on macrumors have noted the same issue, and have narrowed it down to having AFT installed.
I'm getting the same problem, and I too have AFT installed, but I won't be removing it any time soon as it's the only way to get anything to/from my Android devices.
diskutil unmountDisk /dev/diskX (X is number of disk from step 1)
sudo dd if=/dev/urandom of=/dev/diskX bs=1000000 (X is number of disk from step 1)
Then wait! (no time indicator)
for me sticking the SD card in and pulling it a bit out again ( just a few mm ) seems to get it mounted.
There's even a video that explains how to put it in and pull it out a bit here
But I find that putting it in under an angle works better:
Sticking the card in under a angle with the cut off corner against the top of the SD slot and then pushing the ...
SD cards are categorized in different classes according to their speed. Generally, SD cards perform even slower than a normal HDD drive which is why I do not recommend using them as a major storage option.
You should invest in the most expensive type of SD to have an acceptable I/O performance. E.g. an Ultra High Speed SD card (UHS) such as this one.
Connect the memory card and launch the program Image Capture (found in the Utilities folder in both /Applications/ or in Launchpad, if you're running Lion. In the lower left corner of the screen, there should be a menu that says Connecting this camera opens...; from the menu, select iPhoto from the list.
This should make iPhoto launch when you connect this ...
Yes! You can change the volume from a removable device to a fixed disk by flipping the removable bit. Lexar made an application for Windows called 'Lexar BootIt', a well known application for this task.
I found a solution involving DD, but I have not tested it and I'd severely recommend backing up your card before doing anything with DD/Terminal. I created ...
Open up a terminal and check out the following command:
newfs_msdos -- construct a new MS-DOS (FAT) file system
newfs_msdos [-N] [-B boot] [-F FAT-type] [-I volid] [-O OEM]
[-S sector-size] [-a FAT-size] [-b block-size]
[-c cluster-size] [-e dirents] [-f format] [-h heads]
[-i info] ...
The following procedure should format your SD card to make it usable again and cause bad sectors on the card to be remapped if that is part of your problem. Warning, erasing the wrong drive could make you cry so make sure that you know what you are doing.
Before inserting the SD card into your Mac, make sure that the write protect (lock) switch is turned ...
I had a PNY 32gb SD Card. Spent hours trying to find out how to make it re-writeable. Well the answer is simple. The slider on the left side of the card must be "up" (the read-writable position) BUT ALSO the tiny "notch" opposite the slider must be covered with a piece of tape. It's really the opposite of the old video tapes, which we had to break the tab if ...
Assuming Disk Utility doesn't work, try formatting the card using the SD Association's official formatting utility. It may seem a bit silly to download a program just for formatting SD cards, but I've had it fix all sorts of strange errors when nothing else worked, including disk utility / diskutil.
I know this is an old question but I just found it via a Google search. Check out the Nifty MiniDrive which is exactly what you are describing.
Check out this low profile micro SD card reader for the Raspberry Pi computer:
$6 versus $25 for the Kickstarter polished Nifty Drive (I actually bought one for a friend).
It appears to work according to several reports:
There has been some concern that Apple lists the MacBook Pro models on
its web site as having an SDXC card slot, for high-capacity SD cards,
and only lists the card reader on the Air as an SD card one. We ...
Three things will need to come together for this to work:
The Filesystem on the SD card needs a .fseventsd hidden directory and the system to track all changes (which typically gets created automagically when you format the card as HFS+) I haven't seen anyone hack Time Machine to back up filesystems that don't register with Apple's file system events API.