this post was submitted on 03 Aug 2025
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Linux Phones

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Community about running GNU/Linux on phones. Projects like Ubuntu Touch, Plasma Mobile, PostmarketOS, Mobian etc. Either on former Android phones or hardware like the PinePhone.

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Has anyone actually successfully installed PostmarketOS on an old device recently? I've had a long struggle through trying to prepare a Nexus 7 (2012) and the result seems to be a dead device before I even got to actually installing PostmarketOS.

The rough steps I followed are listed here:

  • Create backups
  • Get SBK
  • Build and prepare U-Boot
    • Actually flashing U-Boot seems to be where things went wrong
      • Running ./run_bootloader.sh -s T30 -t ./bct/grouper.bct -b ../re-crypt/repart-block.bin or ./run_bootloader.sh -s T30 -t ./bct/grouper.bct -b ../generated-wheelie-blobs/AndroidRoot/blob.bin from fusee-tools hung on waiting for bootloader to initialize
      • Running ./run_bootloader.sh -s T30 -t ./bct/grouper.bct -b ../u-boot/u-boot-dtb-tegra.bin failed like this
      • skipping that step and running ./utils/nvflash_v1.13.87205 --resume --rawdevicewrite 0 1024 ../re-crypt/repart-block.bin hung on [resume mode]
      • Consulting a different version of the docs and running ./wheelie --blob ./generated-wheelie-blobs/AndroidRoot/blob.bin seemed to work so I ran ./nvflash --resume --rawdevicewrite 0 1024 ./re-crypt/repart-block.bin which also seemed to work
      • I then powered off as instructed and the device has been completely unresponsive since

I've tried connecting to a charger, disconnecting and reconnecting the battery, and every combination of holding down buttons but it appears to be completely dead. Any suggestions as to what I did wrong or anything I might be able to do now? Obviously it's not the end of the world to have lost a 13 year old tablet that was just gathering dust, but at the moment I'm not feeling positive about ever trying this again on another device!

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[–] anon5621@lemmy.ml 2 points 6 months ago* (last edited 6 months ago) (1 children)

U need to reflash uboot and it only possible via dissambly cause uboot is bios of phones Any button will not work because button responses is coming from uboot firmware

[–] smeg@feddit.uk 2 points 6 months ago (1 children)
[–] the_lone_wolf@lemmy.ml 1 points 5 months ago (1 children)

Uart! Tx & Rx pin maybe or you have to use qualcomm download mode

[–] smeg@feddit.uk 1 points 5 months ago (1 children)

Any guides or further reading you can point me to for this?

[–] the_lone_wolf@lemmy.ml 1 points 5 months ago

Search about qualcomm edl mode, firehouse programmer for your chipset

[–] dslul@fosstodon.org 1 points 1 month ago (1 children)

@smeg the correct steps were:
1 - preload u-boot with command ./run_bootloader.sh -s T30 -t ./bct/grouper.bct -b ../re-crypt/u-boot-dtb-tegra.bin (note this is the unencrypted bootloader) AND simultaneously press the volume down button - it will enter the u-boot menu
2 - run the re-crypt script with additional parameter --split (to create two files)
3 - from the tablet, select fastboot mode from the u-boot menu, then follow the guide (fastboot flash 0.1 bct.img and fastboot flash 0.2 ebt.img)

[–] dslul@fosstodon.org 1 points 1 month ago (1 children)

@smeg to unbrick you can follow this guide https://github.com/tofurky/tegra30/_debrick?tab=readme-ov-file#Nexus-7-2012-WiFi-Debrick

I think it's sufficient to enter APX mode (follow point 3 on the above link) and then do the commands I posted

[–] smeg@feddit.uk 1 points 1 month ago

Thanks, I'll have a try when I get some time to look at this again

[–] quixote@mastodon.nz 0 points 6 months ago (1 children)

@smeg Oh man. Good luck. I hope somebody here has some idea what to do. (@sideofburritos has some excellent how-to videos. Might be worth a look.)

[–] smeg@feddit.uk 1 points 5 months ago

Apparently nobody does :(

A quick search for sideofburritos isn't giving me anything, did you have a particular video in mind?