# WP8548 - Custom Yocto image not working

**URL:** <https://forum.legato.io/t/wp8548-custom-yocto-image-not-working/2342>\
**Category:** Legato Linux distribution (Yocto project)\
**Created:** [February 10, 2017, 2:06pm UTC](https://forum.legato.io/t/wp8548-custom-yocto-image-not-working/2342 "2017-02-10T14:06:31Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![novotnyv](https://avatars.discourse-cdn.com/v4/letter/n/838e76/32.png) [@novotnyv](https://forum.legato.io/u/novotnyv)\
**Post date:** [February 10, 2017, 2:06pm UTC](https://forum.legato.io/t/wp8548-custom-yocto-image-not-working/2342/1 "2017-02-10T14:06:31Z")

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Hi,  
I have MangOH with WP8548 running this firmware:  
`root@swi-mdm9x15:~# cm info all Device: WP8548 IMEI: 359377060012340 FSN: LL540300071003 Firmware: SWI9X15Y_07.11.11.00 r33161 CARMD-EV-FRMWR1 2016/09/20 16:36:44 Bootloader: SWI9X15Y_07.11.11.00 r33161 CARMD-EV-FRMWR1 2016/09/20 16:36:44 root@swi-mdm9x15:~# legato version 16.07.0_cd4985660a55cc9a6f9a2ed28bcc757e `  
and I am trying to use own build of Yocto.  
But after flashing with `swiflash -m WP85XX -i yocto_wp85.cwe` the device does not boot and is stuck at  
`Android Bootloader - UART_DM Initialized!!! [10] ERROR: No misc partition found`  
Is there any way to debug this?

My idea was to flash just the rootfs as I am ok with the stock kernel. But I can’t enable the fastboot mode, which according to [Firmware release notes 12.2](http://source.sierrawireless.com/resources/legato/wp85crn/) should be available again since release 11 and which I have enabled:  
`AT!CUSTOM? !CUSTOM: ISVOICEN 0x01 GPIOSARENABLE	0x01 GPSENABLE 0x01 WAKEHOSTEN 0x83 NMEAENABLE 0x01 GOBIIMEN 0x01 USBECMRNDISOPTION	0x01 HSICENABLE 0x01 SINGLEAPNSWITCH	0x01 SIMLPM 0x01 BOOTQUIETDISABLE	0x01 FASTBOOTEN 0x01 `  
So my questions are:

1. Is there a way to debug kernel loading
2. Is Fastboot mode working and if so how should I enable it?

Thank you  
Viktor

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**Author:** ![rio99](https://avatars.discourse-cdn.com/v4/letter/r/d78d45/32.png) [@rio99](https://forum.legato.io/u/rio99)\
**Post date:** [February 13, 2017, 7:15am UTC](https://forum.legato.io/t/wp8548-custom-yocto-image-not-working/2342/2 "2017-02-13T07:15:51Z")

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The most reliable way to flash custom image is fastboot.  
So instead of flashing .cwe file try to flash kernel (2k.img) and rootfs (2k.ubi) separately as mentioned [here](http://legato.io/legato-docs/latest/yoctoLegatoOverview.html).  
To enter fastboot mode use UART console, in some reason I can’t enter fastboot mode through ECM or Ethernet connected console.

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<div class="post-metadata">

**Author:** ![novotnyv](https://avatars.discourse-cdn.com/v4/letter/n/838e76/32.png) [@novotnyv](https://forum.legato.io/u/novotnyv)\
**Post date:** [February 15, 2017, 6:11pm UTC](https://forum.legato.io/t/wp8548-custom-yocto-image-not-working/2342/3 "2017-02-15T18:11:11Z")

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Well, the problem was that I couldn’t get fastboot utility on my Ubuntu 16.04.1 to detect the Mangoh( and I do have the udev rule installed). Anyway it was solved for now by using the provided virtual image on a Windows 10 PC instead, where the fastboot works. If I ever figure out why it isn’t working on my Ubuntu I will update this thread. Thank you for your help.