Qualcomm msm8k GPT Abnormal cause analysis problem with no boot

The problem analysis process is as follows:

One

MSM8916 gpt probability problem: After downloading software tools using qpst emmc software download, the system cannot be powered on. For example, the following drawings:

Log parsing is the UserData partition did not succeed Mount.

Watermark/2/text/ahr0cdovl2jsb2cuy3nkbi5uzxqvrnlib24=/font/5a6l5l2t/fontsize/400/fill/i0jbqkfcma==/dissolve/70 /gravity/center ">

Two

ADB shell Ls/dev/block display. Machine that failed to boot. Less than the normal boot of the machine one partition: MMCBLK0P28, this partition is the UserData partition!

I have also included an article "Add_partition function learning" in my transfer and supplementary content.

/dev/block/mmcblk0pxx These partitions are created from GPT content and therefore suspect GPT content errors, causing the user partition to not be created successfully.

[Email protected]/# CD dev/block/
[Email protected]:/dev/block # ls

Mmcblk0
Mmcblk0p1
Mmcblk0p10
Mmcblk0p11
Mmcblk0p12
Mmcblk0p13
Mmcblk0p14
Mmcblk0p15
Mmcblk0p16
Mmcblk0p17
Mmcblk0p18
Mmcblk0p19
Mmcblk0p2
Mmcblk0p20
Mmcblk0p21
Mmcblk0p22
Mmcblk0p23
Mmcblk0p24
Mmcblk0p25
Mmcblk0p26
Mmcblk0p27
MMCBLK0P28 P28 partition with normal boot
Mmcblk0p3
Mmcblk0p4
Mmcblk0p5
Mmcblk0p6
Mmcblk0p7
Mmcblk0p8
Mmcblk0p9
Mmcblk0rpmb

Three

Use the DD command to read the GPT data from the MMC device mmcblk0 , and read a copy of the normal power-on and the no-boot.

Four, using binary comparison tool hexcmp control two parts of the contents of the GPT, there are two main anomalies, such as the following two diagram:

Watermark/2/text/ahr0cdovl2jsb2cuy3nkbi5uzxqvrnlib24=/font/5a6l5l2t/fontsize/400/fill/i0jbqkfcma==/dissolve/70 /gravity/center ">

To be able to see GPT headerGPT header CRC and partition array CRC different, first LBA, last LBA different.

For example, with:

is a comparison of the contents of the Partiton array. Can see different end LBA for the UserData partition.

The GPT content that fails to boot is compared to the default build Gpt_main0.bin, and the end LBA of the UserData partition is found to be equal to the build.

The UserData partition is the last partition of the entire EMMC, and the end LBA of the last partition of the different EMMC size is unknown to the build phase. So the build is just a default value.

The LBA value must be actively updated by the download tool itself.

Watermark/2/text/ahr0cdovl2jsb2cuy3nkbi5uzxqvrnlib24=/font/5a6l5l2t/fontsize/400/fill/i0jbqkfcma==/dissolve/70 /gravity/center ">

Four

From the above analysis to be able to know qpst emmc software Download tool did not update UserData end LBA. or the update fails.

So, how does it prove that the tool did not write this LBA? or write a failure? Or is it written in the wrong content?

Use the Winhex tool to intercept the contents of the GPT header and GPT partition arrary from the GPT content that cannot be powered on.

Use the As-crc32.exe tool. The CRC is computed for the contents of the GPT header and GPT partition array, respectively. Tools such as the following:

By comparing the CRC. The two CRC in the GPT header that the computer is out of CRC is equal.

Therefore, it is possible to prove that the userdata end in GPT is not a write failure or is not written.

Instead, qpst emmc software Download the wrong content of the finalized tool.

Conclusion: From the analysis above, it can be proved that qpst emmc software Download tool is a problem.

Five

Solution suggestions.

Update Qpst software version number, the latest version number supports a new download tool using the Firehose protocol: Qfil,

Replace qpst emmc software download. Qfil is more stable and better used. For example, with:

Watermark/2/text/ahr0cdovl2jsb2cuy3nkbi5uzxqvrnlib24=/font/5a6l5l2t/fontsize/400/fill/i0jbqkfcma==/dissolve/70 /gravity/center ">

References:

80-n7350-1_b_guid_partition_tables_programming.pdf

Uefi_2_4_errata_b.pdf

Copyright notice: This article Bo Master original articles, blogs, without consent may not be reproduced.

Qualcomm msm8k GPT exception cause analysis failed to boot problem