How to Flash with MacOS 11(Big Sur)-Checksum Error

I’ve been working on this for weeks and dizzy from reading different forums on what to do and the issue. Will someone just please tell me what to do? I’ve been flashing USB sticks for years and never had this many issues.

Here is what I’m using:
MacMini MacOS 11.2.3
MacBook Catalina
Two different carriers for SD cards
Three different SanDisk cards
Etcher, dd, and Rasberry Pi Imager

All of the combinations give me the same error. Here is the last thing I tried. I reformatted the card as MBR Fat 32. I run Etcher on the card.
MacOS then asks: Eject, Ignore, Initialize…

I’m not sure which one to pick. I think Ignore will not allow me to do anything with the drive so I pick Initialize. Now the card shows an Apple Partition Map disk and a FAT12 volume with 5.1M.

I’ve tried this with a many different Raspberry Pi OSes. The last one I used is Buster. This has me so aggravated I can’t think straight anymore. I’m looking for a straight up answer and yes I’ve rebooted:)

Hi, ignoring the message should be fine, it just means the OS won’t perform any operations on the target you just connected and Etcher will still be able to read it.
Now on the specific issue, did you try changing media reader? So if it’s a sdcard slot on your mac, trying with a usb card reader for example, or changing usb reader if you have one spare, as it can make a difference in some cases

Hi Thundron. Thank you for the response. I would not be bothering anyone if it worked. Nothing comes up on my Pi when I put the chips in it. I have two USB media readers I’m using: CoCooka and Sinstar. I have the same results with either one.

Should I Etcher create an Apple partition and FAT12 volume when flashing a Raspberry PI OS? I thought it would be FAT16 or 32.

Oddly, I had a similar issue on downloaded balena project images. I found the solution was to OPEN the image first, then unmount it and then open etcher and re-try to flash from the image.

Not sure why it works but it always does for me.

@drewgolden I’ve worked with computers a long time, but not with data. I’m more on the networking side. I guess I’ve been spoiled because it always just worked before. So I don’t understand what you are saying. Are you saying delete Etcher from Applications and download again. Then open it, cancel the install, unmount it, and then install from the dmg file to create the app file? Or are you talking about the RaspOS file?

I’m going out of town in a bit where there is no Internet until Sunday so when I don’t reply back it is not because I’m not interested and will get back to you by Monday.

Hi @anom, are these new SD cards? Have you tried doing “Initialize” on one of them? What are the results?

Do you get any errors on Etcher itself?

Could you post the Etcher console output (you can get it by doing Cmd+I or through the View Menu > Toggle developer tools). Could you also share your Etcher version?

Thank you

One card was new and the other one was not. I can write files to both. What would tell me if a card was bad? I ran checks on both of them. I have tried Initialize before and after flashing. I’ve tried flashing probably 20-30 times with different combinations.

I get the checksum error that is discussed in a lot of forums. I’m using version 1.5.113 right now. I did not know about the Cmd+i option. I’ll try that Monday and let you know.

Are you trying to burn an OS image file? Mac OS can open the image file to validate it’s a good image. I was getting errors from etcher on images I would download from So I discovered that OPENING the images and then closing / unmounting the image was enough to allow etcher to open and write the image to an SD card. For example I downloaded balena-cloud-Balena_ADS-B-raspberrypi4-64-2.73.1+rev1-dev-v12.4.6.img but it would not write with etcher to the sd card. Open it, then unmount it - and magically it works and will burn to the SD card without error.

Here is the log data from the Developer Tools when I tried to flash an ISO to a card. I’m going to try DrewGolden’s idea now.

Verifying 1 device, 99% at 9.80 MB/s (total 9.80 MB/s) eta in 1s with 0 failed devices

gui.js:56875 Mon Apr 12 2021 12:59:21 GMT-0400 (Eastern Daylight Time) Validation error ({“image”:{“size”:3091660800,“name”:“2021-01-11-raspios-buster-i386.iso”,“hasMBR”:true,“partitions”:[{“offset”:2697216,“size”:5128192,“type”:239,“index”:1}],“extension”:“iso”,“path”:"/Volumes/Rasberry Pi/2021-01-11-raspios-buster-i386.iso"},“drives”:[{“size”:64424509440,“isVirtual”:false,“enumerator”:“DiskArbitration”,“logicalBlockSize”:512,“raw”:"/dev/rdisk3",“error”:null,“isReadOnly”:false,“displayName”:"/dev/disk3",“blockSize”:512,“isSCSI”:false,“isRemovable”:true,“device”:"/dev/disk3",“busVersion”:null,“isSystem”:false,“busType”:“USB”,“isCard”:false,“isUSB”:true,“devicePath”:“IODeviceTree:/PCI0@0/XHC1@14”,“mountpoints”:,“description”:“Generic MassStorageClass Media”,“isUAS”:null,“partitionTableType”:null}],“driveCount”:1,“uuid”:“279a50ca-a183-484d-bc6f-daae9448a0f9”,“flashInstanceUuid”:“279a50ca-a183-484d-bc6f-daae9448a0f9”,“sample”:0.1,“applicationSessionUuid”:“75d627b7-24e9-4741-97be-3a5404659629”,“flashingWorkflowUuid”:“84fdd1b8-e7f2-4034-a825-f3b2a6ede2c6”})

gui.js:6038 Verifying 1 device, 99% at 10.20 MB/s (total 10.20 MB/s) eta in 0s with 0 failed devices

gui.js:56875 Finish: 3089104896

gui.js:56875 Terminating IPC server

gui.js:56875 Flash results

  1. {results: {…}, cancelled: false, skip: false}

gui.js:56875 Mon Apr 12 2021 12:59:23 GMT-0400 (Eastern Daylight Time) Done ({“image”:{“size”:3091660800,“name”:“2021-01-11-raspios-buster-i386.iso”,“hasMBR”:true,“partitions”:[{“offset”:2697216,“size”:5128192,“type”:239,“index”:1}],“extension”:“iso”,“path”:"/Volumes/Rasberry Pi/2021-01-11-raspios-buster-i386.iso"},“drives”:[{“size”:64424509440,“isVirtual”:false,“enumerator”:“DiskArbitration”,“logicalBlockSize”:512,“raw”:"/dev/rdisk3",“error”:null,“isReadOnly”:false,“displayName”:"/dev/disk3",“blockSize”:512,“isSCSI”:false,“isRemovable”:true,“device”:"/dev/disk3",“busVersion”:null,“isSystem”:false,“busType”:“USB”,“isCard”:false,“isUSB”:true,“devicePath”:“IODeviceTree:/PCI0@0/XHC1@14”,“mountpoints”:,“description”:“Generic MassStorageClass Media”,“isUAS”:null,“partitionTableType”:null}],“driveCount”:1,“uuid”:“279a50ca-a183-484d-bc6f-daae9448a0f9”,“status”:“finished”,“flashInstanceUuid”:“279a50ca-a183-484d-bc6f-daae9448a0f9”,“errors”:[{“name”:“Error”,“description”:“Generic MassStorageClass Media”,“code”:“EVALIDATION”,“device”:"/dev/disk3"}],“devices”:{“failed”:1,“successful”:0},“bytesWritten”:3089104896,“sourceMetadata”:{“size”:3091660800,“name”:“2021-01-11-raspios-buster-i386.iso”,“blocks”:[{“blocks”:[{“offset”:0,“length”:3091660800}]}],“blockmappedSize”:3091660800},“sample”:0.1,“applicationSessionUuid”:“75d627b7-24e9-4741-97be-3a5404659629”,“flashingWorkflowUuid”:“84fdd1b8-e7f2-4034-a825-f3b2a6ede2c6”})

This may not matter, but the card will not eject with the Disk Utility app or unmountDisk in a terminal after running Etcher. I close Etcher when done because the app tells me another app is still using the card. The command: ‘diskutil unmountDisk /dev/disk3’ says unmounting worked: ‘Unmount of all volumes on disk3 was successful’, but the card still shows up:
/dev/disk3 (external, physical):
0: Apple_partition_scheme *64.4 GB disk3
1: Apple_partition_map ⁨⁩ 4.1 KB disk3s1
2: Apple_HFS ⁨⁩ 5.1 MB disk3s2

Opening the image file, unmounting, and then running Etcher also failed:

Verifying 1 device, 20% at 9.80 MB/s (total 9.80 MB/s) eta in 122s with 0 failed devices

gui.js:56875 Mon Apr 12 2021 13:46:50 GMT-0400 (Eastern Daylight Time) Validation error ({“image”:{“size”:1862270976,“name”:“2021-01-11-raspios-buster-armhf-lite.img”,“hasMBR”:true,“partitions”:[{“offset”:4194304,“size”:268435456,“type”:12,“index”:1},{“offset”:272629760,“size”:1589641216,“type”:131,“index”:2}],“extension”:“img”,“path”:"/Volumes/Rasberry Pi/2021-01-11-raspios-buster-armhf-lite.img"},“drives”:[{“size”:64424509440,“isVirtual”:false,“enumerator”:“DiskArbitration”,“logicalBlockSize”:512,“raw”:"/dev/rdisk3",“error”:null,“isReadOnly”:false,“displayName”:"/dev/disk3",“blockSize”:512,“isSCSI”:false,“isRemovable”:true,“device”:"/dev/disk3",“busVersion”:null,“isSystem”:false,“busType”:“USB”,“isCard”:false,“isUSB”:true,“devicePath”:“IODeviceTree:/PCI0@0/XHC1@14”,“mountpoints”:,“description”:“Generic MassStorageClass Media”,“isUAS”:null,“partitionTableType”:null}],“driveCount”:1,“uuid”:“d34bc56f-b3fc-46ea-80a5-57cd572eff2d”,“flashInstanceUuid”:“d34bc56f-b3fc-46ea-80a5-57cd572eff2d”,“sample”:0.1,“applicationSessionUuid”:“2aebccf3-a566-47eb-bb60-be7fd6b4f4bc”,“flashingWorkflowUuid”:“0d46b740-8eca-49a1-99ec-5c8481a96000”})

gui.js:6038 Verifying 1 device, 20% at 9.80 MB/s (total 9.80 MB/s) eta in 121s with 0 failed devices

gui.js:56875 Finish: 314572800

gui.js:56875 Terminating IPC server

gui.js:56875 Flash results

  1. Object

gui.js:56875 Mon Apr 12 2021 13:46:52 GMT-0400 (Eastern Daylight Time) Done ({“image”:{“size”:1862270976,“name”:“2021-01-11-raspios-buster-armhf-lite.img”,“hasMBR”:true,“partitions”:[{“offset”:4194304,“size”:268435456,“type”:12,“index”:1},{“offset”:272629760,“size”:1589641216,“type”:131,“index”:2}],“extension”:“img”,“path”:"/Volumes//Rasberry Pi/2021-01-11-raspios-buster-armhf-lite.img"},“drives”:[{“size”:64424509440,“isVirtual”:false,“enumerator”:“DiskArbitration”,“logicalBlockSize”:512,“raw”:"/dev/rdisk3",“error”:null,“isReadOnly”:false,“displayName”:"/dev/disk3",“blockSize”:512,“isSCSI”:false,“isRemovable”:true,“device”:"/dev/disk3",“busVersion”:null,“isSystem”:false,“busType”:“USB”,“isCard”:false,“isUSB”:true,“devicePath”:“IODeviceTree:/PCI0@0/XHC1@14”,“mountpoints”:,“description”:“Generic MassStorageClass Media”,“isUAS”:null,“partitionTableType”:null}],“driveCount”:1,“uuid”:“d34bc56f-b3fc-46ea-80a5-57cd572eff2d”,“status”:“finished”,“flashInstanceUuid”:“d34bc56f-b3fc-46ea-80a5-57cd572eff2d”,“errors”:[{“name”:“Error”,“description”:“Generic MassStorageClass Media”,“code”:“EVALIDATION”,“device”:"/dev/disk3"}],“devices”:{“failed”:1,“successful”:0},“bytesWritten”:314572800,“sourceMetadata”:{“size”:1862270976,“name”:“2021-01-11-raspios-buster-armhf-lite.img”,“blocks”:[{“blocks”:[{“offset”:0,“length”:317718528}]},{“blocks”:[{“offset”:406847488,“length”:101711872}]},{“blocks”:[{“offset”:512753664,“length”:793772032}]},{“blocks”:[{“offset”:1307574272,“length”:189792256}]},{“blocks”:[{“offset”:1522532352,“length”:1048576}]},{“blocks”:[{“offset”:1524629504,“length”:6291456}]},{“blocks”:[{“offset”:1561329664,“length”:1048576}]},{“blocks”:[{“offset”:1563426816,“length”:1048576}]},{“blocks”:[{“offset”:1632632832,“length”:16777216}]},{“blocks”:[{“offset”:1650458624,“length”:2097152}]},{“blocks”:[{“offset”:1656750080,“length”:8388608}]},{“blocks”:[{“offset”:1673527296,“length”:58720256}]}],“blockmappedSize”:1498415104},“sample”:0.1,“applicationSessionUuid”:“2aebccf3-a566-47eb-bb60-be7fd6b4f4bc”,“flashingWorkflowUuid”:“0d46b740-8eca-49a1-99ec-5c8481a96000”})