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Nexus 7 bootloader issues (unable to update to 4.23)

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redrol
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Unhappy Nexus 7 bootloader issues (unable to update to 4.23)

So this is kind of a long story but basically I had a Nexus 7 8GB model. I bricked it by destroying the bootloader and so I sent it back for RMA.

When the thing came back it worked but was laggy as hell. I did all the normal erases and whatnot, even flashed back to stock, still laggy. I figure the EMMC was toast. So I purchased a used Nexus 7 16GB motherboard from ebay.

The new motherboard worked but came encrypted so it booted and asked for the password. Of course, not knowing the password, I had to get into recovery and do a data reset. After all that I was able to root and a Cyanogen mod based ROM.

The problem I currently have is this: I am unable to flash or update the bootloader which is stuck on 4.13. When I try and push the kitkat bootloader via fastboot I get "BAD PARAMETER" and am unable to get passed this.

In case anyone cares I was able to follow the bricksafe flatline procedure and captured the existing bootloader partition blob which is now saved to my computer. I have tried to push that bootloader back to the device and that works but I CANNOT flash the damn 4.23 (kit kat) bootloader.


Basically my Nexus 7 charges at a snails pace now but works. Any help is very much appreciated!
 
Lim Wee Huat
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I donít think the outdated bootloader is the cause of slow charging. Iím using the latest 4.23 and it charges like a snail too.
 
bftb0
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possibly you are trying to flash (Google-supplied) trash to your bootloader?

[WARNING][URGENT] N7 grouper (2012 WiFi) bootloader .img files from Google
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redrol
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(Last edited by redrol; 17th December 2013 at 04:29 AM.)
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Quote:
Originally Posted by bftb0 View Post
possibly you are trying to flash (Google-supplied) trash to your bootloader?

[WARNING][URGENT] N7 grouper (2012 WiFi) bootloader .img files from Google
I've checked the version of the bootloader, should be ok. Also I have tried flashing 4.13, lower versions, higher versions, etc.. all fail with the 'bad parameter'.

Also I get this when I do 'fastboot getvar all'.. note the size of the bootloader, on other devices this is a 0x000.. type number. Not on mine
Code:
(bootloader) version-bootloader: 4.13
(bootloader) version-baseband: N/A
(bootloader) version-hardware: ER3
(bootloader) version-cdma: N/A
(bootloader) variant: grouper
(bootloader) serialno: 015d32205a3cDERP
(bootloader) product: grouper
(bootloader) secure: no
(bootloader) unlocked: yes
(bootloader) uart-on: no
(bootloader) partition-size:bootloader:
(bootloader) partition-type:bootloader: emmc
(bootloader) partition-size:recovery: 0x0000000000c00000
(bootloader) partition-type:recovery: emmc
(bootloader) partition-size:boot: 0x0000000000800000
(bootloader) partition-type:boot: emmc
(bootloader) partition-size:system: 0x0000000028a00000
(bootloader) partition-type:system: ext4
(bootloader) partition-size:cache: 0x000000001bb00000
(bootloader) partition-type:cache: ext4
(bootloader) partition-size:userdata: 0x0000000368f00000
(bootloader) partition-type:userdata: ext4
 
bftb0
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Well, before we get too far off into the weeds (flashing) I will first have to agree with Lim Wee Haut - it is pretty unlikely that the bootloader has any effect on charging whatsoever. Tablets that are pure stock can pull 1.8-2A from the Asus OEM charger, so it's not obvious that software is ever the problem.

For instance, when the tablet is booted into the regular OS, it is impossible for the bootloader to be active. It's not like a PC BIOS (where software interrupt calls from the OS can be vectored through the BIOS). At most, the bootloader could set some hardware registers (e.g. in the SMB USB/charger chip) prior to loading the Linux kernel, but once the kernel is active, it is free to reprogram the hardware through it's device driver(s).

And what about when the tablet is completely off? This situation is less obvious to me - after all, when you plug the N7 onto the charger, a "charging animation" is displayed, and *something* is painting the screen... but I don't really know if that activity is being run by bootloader code or something in the tegra3 "miniloader".(The Tegra3 has a small ROM area in it for storing a tiny executable that can be programmed by the system designer and then protected by use of private keys)

In any event, the problem could be the charger, the battery, the cable, or any number of other things. Note that it is possible to observe the charging current using the "Current Widget" app plus a kernel that has the bq2745 current monitor patch in it, but you need to crank down the max clock and screen brightness - what you observe via that app is literally the current flowing ONLY in to the battery, not the total current provided by the charger. That means - because you can only get the tablet down to about 300 mA of consumption with the screen on - that the most charging current you will observe that way is about 1400-1500 mA on a charger that can put out 1.8A @ 5V.

OK, back to the flashing thing: I skimmed through two of the threads related to the "bricksafe flatline" hack, and I got the impression that once you have used that hack, there is no going back to fastboot for flashing bootloaders any longer - you are stuck using nvflash/wheelie thereafter. Is that incorrect? Or was it just that using fastboot with that patched bootloader (4.13-hacked?) causes flashing problems? It would be consistent with what you are reporting.

Sorry for the apparent randomness of this reply, just throwing out some ideas.
"I'm gonna start coding placebo apps. That way I will be sure that the complaints are real and the praises hollow."
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