dd vs fastboot flash

[Guest isambard]

after a CWR installation gone wrong, i was left with a trashed recovery.

i initially tried to recover by:

busybox dd bs=4096 if=/data/recovery.img of=/dev/mtd/mtd0

however, this managed to get it so that the green android came up, but the recovery image was not installed properly

with fastboot, enabled, i then did:

fastboot flash recovery recovery.img

which then managed to get CWR loaded.

But I wondered, does fastboot do anything other than dd the image onto the partition? is there any reason why the dd alone should not have been enough?

[Guest hecatae]

i usually use bs=8192 when using dd, and where was the recovery.img located?

busybox dd bs=4096 if=/sdcard/recovery.img of=/dev/mtd/mtd0 would work if the recovery.img was located on the sdcard, is there a reason you pointed it at the data partition?

[Guest fonix232]

The MTD partition after flashing is not the same as the IMG file you were trying to flash.

As an example, take dd, dump the content of MTD0 into the SD card, then move it back. It will work. Moving an image like that WILL NOT. Not same file system etc.

BTW you can use flash_image on phone if you wanna flash the recovery partition. Usage:

flash_image [partition] [path_to_img]

You need to be in root mode for that!

[Guest isambard]

i usually use bs=8192 when using dd, and where was the recovery.img located?

busybox dd bs=4096 if=/sdcard/recovery.img of=/dev/mtd/mtd0 would work if the recovery.img was located on the sdcard, is there a reason you pointed it at the data partition?

i tried putting the recovery from both data and on sdcard (tried sdcard first but then used data in case the sdcard was corrupted).

[Guest isambard]

The MTD partition after flashing is not the same as the IMG file you were trying to flash.

As an example, take dd, dump the content of MTD0 into the SD card, then move it back. It will work. Moving an image like that WILL NOT. Not same file system etc.

BTW you can use flash_image on phone if you wanna flash the recovery partition. Usage:

flash_image [partition] [path_to_img]

You need to be in root mode for that!

thanks. the strange thing is that i originally took a dump of the recovery partition by using dd and tried to dump that back but maybe i made a mistake on the original dump.

thanks again for the tip. i'll try it using this tool and dd again. i guess i must have made a mistake on the original dump.