[HN Gopher] Android Booting Shenanigans
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Android Booting Shenanigans
Author : cab404
Score : 86 points
Date : 2022-06-17 09:07 UTC (13 hours ago)
(HTM) web link (topjohnwu.github.io)
(TXT) w3m dump (topjohnwu.github.io)
| [deleted]
| thrdbndndn wrote:
| I have zero background/knowledge about this topic, so forgive me
| if it's a stupid question; but the article is very confusing to
| me.
|
| In the terminology section, it says initramfs:
| a section in Android's boot image that the Linux kernel will use
| as rootfs
|
| And SAR: System-as-root. That is, the device
| uses system as rootdir instead of rootfs
|
| In Boot Methods section, it says something like
| The kernel uses initramfs as rootdir ..
|
| So far, it has
|
| * initramfs as rootfs
|
| * system as rootdir (or "rootfs as rootdir" if no SAR)
|
| * initramfs as rootdir
|
| I get that the whole point of this article is about "A as B" for
| some booting shenanigans, but this mapping relationship doesn't
| make sense to me. rootfs somehow appears in both ends.
|
| Also, for method A and C, it says "uses initramfs as rootdir" but
| the table lists "rootfs" instead of initramfs?
| gizmo686 wrote:
| The terminology is confusing and the article isn't doing a good
| job of explaining it.
|
| "Rootfs" is an im-memory virtual filesystem used to hold the
| root. The bootloader will read the initramfs into ram before
| executing the kernel, then the kernel will use that in memory
| data to construct the rootfs filesystem. For non root
| partitions you would use a loopback device or tmpfs.
|
| Since system is a normal partition, the kernel can use the
| normal disk/filesystem drivers as a root device.
| Snuupy wrote:
| While we're on the topic of rooting, only Google, Sony, Xiaomi,
| Asus, Motorola, OnePlus, Samsung (Exynos only, breaks eFUSE) are
| bootloader unlockable.
|
| Of the above, only Google has what I would consider "proper"
| software support.
|
| At this point, I refuse to buy anything that I can't bootloader
| unlock and does not have proper software support because of
| planned obsolescence stemming from a lack of software updates.
|
| Blacklisted for not being able to bootloader unlock: Huawei,
| Vivo, Samsung (Qualcomm), Nokia, Pixel (Verizon US variant).
| Georgelemental wrote:
| There is also Fairphone
| fsflover wrote:
| And Librem 5, and Pinephone.
| Snuupy wrote:
| EU only but a viable option there
| mmastrac wrote:
| I'd kill for a Fairphone reseller in NA. I bought one from
| eBay with markup (running my FP4 in Canada and have roamed
| in the US with it). It's a great phone that needs more NA
| exposure.
| tslocum wrote:
| I have been using a Fairphone 3 in NA since it was
| released. As long as the device supports the same
| frequencies used by your American cell carrier, it will
| work well. Any package forwarding service may be used to
| receive a Fairphone in NA.
| fragmede wrote:
| Since there are only 3 major carriers, mind sharing which
| one you're on, assuming you're on one of them?
| phs wrote:
| Rocked an unlocked LG v20 (us996) w/ lineage for a few years.
|
| The modem lacks the firmware for VoLTE which is now becoming
| required in the US as the 3G towers are being retired.
|
| It's being retired for a pine phone. So far postmarketos is
| delightful, VoLTE works, and we're about to see if waydroid is
| going to play ball.
| madduci wrote:
| "proper software support" comes when the you get blobs and
| sources. Until now, only Google does it, the other rather
| ignore or refuse to release something
| bbds wrote:
| Iirc sony only allows to unlock bootloader on devices listed as
| part of "open devices" program, but there is no relocking
| supported unfortunately. I would buy another device from them
| myself otherwise.
| teddyh wrote:
| What about the F(x)tec Pro1 X? They list LineageOS
| compatibility on their front page.
| zozbot234 wrote:
| Razer phone has LineageOS official support too, as does
| Essential and Fairphone. In general, there are lots of
| smaller OEM vendors that may or may not support bootloader
| unlock, so YMMV there.
| Snuupy wrote:
| They're fine if you don't mind an outdated chipset and paying
| multiple times the cost in hardware value. SD835 was released
| in 2016 and the 10nm samsung process is nowhere as efficient
| as equivalent TSMC arch nor current chips (say, SD870 or even
| the exynos latest gen chips)
| teddyh wrote:
| You seem to be confused; I said the F(x) Pro1 X (shipping
| next month), not the old F(x)tec Pro1.
| elxr wrote:
| Never heard of the brand, the phone looks pretty unique
| from a quick look at their website. But using parentheses
| in your brand name is a bit of a head-scratcher.
| fartcannon wrote:
| That is a tremendously confusing set of names to glance
| at.
|
| Also, it looks like a great phone.
| yjftsjthsd-h wrote:
| I'll grant that it's expensive and on an old chip, but I
| don't think you can compare "multiple times the cost in
| hardware value" if nobody else has the hardware that is
| their headline feature (hardware keyboard).
| [deleted]
| 0daystock wrote:
| Not sure what "proper" support gets you, but I've used unlocked
| OnePlus devices for years without hiccups.
| Ardon wrote:
| Unlocking my OnePlus involved applying on their website for a
| key and waiting a week, which I found to be a serious
| inconvenience to using my new phone as I wanted to. I'd
| consider that disqualifying from being "proper" unlocking,
| since what would I have done if they just said no to my
| application?
| Snuupy wrote:
| Wait til you see Xiaomi's 14 day wait lol
| pxeboot wrote:
| Wasn't this a carrier imposed restriction? I bought my 6t
| directly from OnePlus, and was able to unlock the
| bootloader as easy as a Pixel.
| [deleted]
| Snuupy wrote:
| I'm no stranger to OnePlus devices. I've had a OP5 and 6T.
|
| They have repeatedly released ROMs full of bugs, crashes, and
| required factory resets on major version upgrades. Their
| update lag has increased since being combined with
| Oppo/ColorOS, while their value has decreased/cost has
| increased.
|
| They've peaked in terms of hackability and software support.
|
| Even if we disregarded their (worse than google but better
| than say, Xiaomi/moto) software support, which is more
| important than the hardware itself, OnePlus hardware is
| frequently worse (mic, speakers). The only win you get here
| is a latest gen SoC for pricing that is barely (~10%) cheaper
| than the Samsung counterpart with a worse build quality.
|
| OnePlus' proprietary warp charge isn't doing then any favors
| either. Non-standardized charging is frequently a pain point
| for me when most other devices have moved onto USB-PD.
| beezle wrote:
| I've had a 7T since they came out. I've never had it crash
| or do anything super odd. The one OS complaint I've had
| since day one is the auto-dimming being way too agressive
| and never "learning" what I want. Annoying for sure, not
| sure its a bug though.
|
| As to charging, think they were one of the first (maybe the
| first) with the high speed charging. But I can charge it
| from any old charger, just not as fast.
| encryptluks2 wrote:
| I love the simplicity of the site but a meta "light dark" color-
| scheme tag would go a long way.
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