My initial success at getting the APC to boot from the micro-SD card instead of built-in ram was tempered by another issue..<\/p>\n
Apart from examination of the boot process on the console, I had confirmed that device boots from the micro-SD card when I inadvertently formatted it as EXT3, and the boot process failed with an appropriate error, as the APC version of the kernel doesn’t support this format..<\/p>\n
The problem now, is that the device – somehow – still makes the root \/dev\/ram0, instead of \/dev\/mmcblk0p2, and so is still running a cut-down version of the Linux environment that is built in to the device..\u00a0\u00a0 This is not the OS that normally runs, but is just a bare-bones Linux (with good old BusyBox..), without all the Android-y stuff..\u00a0\u00a0\u00a0\u00a0 I would guess that this is provided for ‘troubleshooting’ purposes..\u00a0\u00a0\u00a0 This is where the lack of any detailed technical documentation is a real frustration!<\/p>\n
The U-Boot boot parameters clearly have root=\/dev\/mmcblk0p2<\/strong> and this ‘diversion’ worked fine with the Dreamplug (which also uses U-Boot), when I changed the boot device from the (flimsy and unreliable) internal micro-SD card slot to the ‘external’ USB SD-Card slot.<\/p>\n Update<\/strong><\/em>:\u00a0\u00a0 It appears the device is ignoring the root=\/dev\/xxxxx parameter entirely.\u00a0\u00a0\u00a0 I set it to root=\/dev\/null<\/strong> and the APC still booted to root=\/dev\/ram0, as before…<\/p>\n I am beginning to think this may be a ‘customised’ version of the kernel boot code, which is set to only allow access to the complete Android system in flash memory, or the minimalist Linux in \/dev\/ram0 – probably there for test\/maintenance purposes..\u00a0\u00a0\u00a0 I should have realised there was something odd, when I examined the original U-Boot parameters, which are consistent with this behaviour..\u00a0\u00a0\u00a0 Ironically, this configuration may well have been designed – with the best of intentions – to stop people compromising the (Android) system by simply plugging in a bootable micro-SD card!<\/p>\n Of course, this is all speculation, in the absence of detailed technical documentation..<\/p>\n So – the challenge continues!<\/p>\n","protected":false},"excerpt":{"rendered":" My initial success at getting the APC to boot from the micro-SD card instead of built-in ram was tempered by another issue.. Apart from examination of the boot process on the console, I had confirmed that device boots from the micro-SD card when I inadvertently formatted it as EXT3, and the boot process failed with an appropriate …<\/span> Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[3,5,6,11,16,19,20],"tags":[89,262,305,325,326,372],"class_list":["post-319","post","type-post","status-publish","format-standard","hentry","category-apc","category-compilation","category-crash-and-burn","category-hacks","category-linux-arm","category-opinion","category-performance-2","tag-apc-2","tag-mmc","tag-problem","tag-rom","tag-root","tag-u-boot"],"_links":{"self":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/319","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=319"}],"version-history":[{"count":0,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/319\/revisions"}],"wp:attachment":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=319"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=319"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=319"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}