corrupt PBP

[jbradley419]

corrupt partition boots to busy box 1.36 i cannot boot to SD card with uboot  Any way to boot to SD card from busy box to reinstall os on EMMC?|

[tophneal]

You could try some of the options given in this SO post: https://askubuntu.com/questions/137655/b...ts-busybox

If those don't work, you can remove the bottom panel of the PBP case, flip the emmc switch to OFF, insert/boot from SD, and as the PBP boots from the SD, flip the switch back toON and use the 2 terminal commands in the wiki to initialize the eMMC and be able to chroot or reflash it from the SD OS

[wdt]

While I have not had to use these commands,,, busybox has fdisk, dd, mount, and fsck
So.... first try a fsck
fdisk -l to find correct partition,, maybe /dev/mmcblk2p2
fsck -y /dev/something
(to fix "bad" uboot)
To blank uboot on emmc... only if you are carefull (in busybox OR os)
fdisk -l ... to find correct mmcblkX,,, what is X
insert usb stick
mkdir /mnt ; mount /dev/sda1 /mnt ; mount ; ls -la /mnt (all cmds should complete without error, someplace to save mbr and 1st 16M)
(is emmc mbr or gpt partitioned, fdisk will tell,, 1 sector for mbr,, 34 sectors for gpt)
dd if=/dev/emmc of=/mnt/emmc.mbr count=(1 OR 34) (emmc appropriate mmcblkX,,, NOT mmcblkXpY)
dd if=/dev/emmc of=/mnt/1st-16.emmc bs=1M count=16
(blanking)
dd if=/dev/zero of=/dev/emmc bs=1M count=16
(restore mbr)
dd if=/mnt/emmc.mbr of=/dev/emmc (so emmc is available for whatever)
the ONLY uboot is on SD, with no SD will not boot, probably will ONLY boot SD****
So, copy the 1st 16MB from some SD to emmc, overwrite with saved emmc mbr
Which uboot? Your guess is as good as mine
But maybe you want to take off back?
**** to boot emmc, rename boot.scr OR extlinux.conf to some other name (on SD)