If you want to backup the boot or recovery image of your device for flashing via fastboot, read and follow the guide below carefully.
1. Connect the device to PC and launch cmd from your adb folder
2. Type the follow commands
This last command will list all the partitions of your device and their mtd block id. For instance:
dev: size erasesize name
mtd0: 000a0000 00020000 “misc”
mtd1: 00480000 00020000 “recovery”
mtd2: 00300000 00020000 “boot”
mtd3: 0fa00000 00020000 “system”
mtd4: 02800000 00020000 “cache”
mtd5: 093a0000 00020000 “userdata”
Take note of the recovery mtd id/number. The continue below: Type
dd if=/dev/mtd/mtd1 of=/sdcard/recovery.img bs=4096
Replace mtd1 with the recovery mtd id of your device that is displayed after the cat proc/mtd command.
The recovery image will be dumped in your sdcard. Get it from there and flash via fastboot.
Note: Root access is required on the device you’re dumping from.
If you have questions, please ask in the comments section.