[Nexus 7 (2013) General] rkhat:
Hi, this is my first time posting here. I noticed there is no guide to increase the system partition size in Nexus 7 (2013). The system partition is only around 880MB making it impossible to flash new ROMs and large package of GApps. This guide is for Nexus 7 (2013) wifi 32GB but it should work for other Nexus 7 (2013) editions and even Nexus 7 (2012) with some numbers changed.

My guide is based on this guide for Nexus 5. Check it out. The only issue with Nexus 7 is that the recovery partition is between the system and userdata partitions in the partition table. So deleting the partitions (which includes recovery partition) and then recreating them with offsets might leave your tablet bricked. If you have a way to unbrick the tablet or you are manly enough, you can try the guide written in the next comment. I haven't tested it. Leave a comment if it works. Anyway from the Nexus 5 guide:

This part is not very accurate. I am not sure about Nexus 5 but in Nexus 7, I have changed the order with great success. Only thing is that you need to restart at the end so that the recovery mode updates the mounting configuration. I am not sure if it works with the stock ROM but it definitely works with a custom ROM.

The downside of my way is that you end up with around 880MB unused memory. You can give it to the cache partition. Otherwise, you have to do the untested one in the next comment.

Before we start, I am not liable if it doesn't work or makes your device unusable. The tested guide below works for me.

[IMG="Nexus 7 2.9GB system partition proof"]http://i.imgur.com/klJAY8w.png[/IMG]

Tested Guide starts here:

Prerequisite:

1. PC (any OS) with adb and fastboot

2. Nexus 7 with TWRP recovery connected to the PC via USB.

3. Get parted from iwf1.com/iwf-repo/parted.rar and extract it into any directory

4. (Optional) System and userdata partitions are wiped out. So backup system and/or data partitions using TWRP recovery

Steps:

1. Open TWRP recovery mode in Nexus 7. Make sure to have the system partition read/write.

2. Go to mount and unmount all partitions you are going to modify (for now system and data).

3. Open PC's command line in parted's directory

4. The next steps are on the command line unless stated:

adb push parted /
adb shell
~ # chmod +x parted
~ # /parted /dev/block/mmcblk0
(parted): unit b
(parted): p

I used unit b to get partition sizes in bytes. So you can resize accurately this way. You will get the following partition table by default. Keep a copy of this partition table (and one with unit compact for easy readability) as reference if you mess up or want to restore to default.

Number Start End Size File system Name Flags
1 67108864B 156745727B 89636864B fat16 radio
2 201326592B 204472319B 3145728B modemst1
3 204472320B 207618047B 3145728B modemst2
4 268435456B 283795455B 15360000B ext4 persist
5 335544320B 336343039B 798720B m9kefs1
6 336343040B 337141759B 798720B m9kefs2
7 402653184B 403451903B 798720B m9kefs3
8 403451904B 406597631B 3145728B fsg
9 469762048B 471298047B 1536000B sbl1
10 471298048B 472834047B 1536000B sbl2
11 472834048B 474931199B 2097152B sbl3
12 474931200B 480174079B 5242880B aboot
13 480174080B 480698367B 524288B rpm
14 536870912B 553648127B 16777216B boot
15 603979776B 604504063B 524288B tz
16 604504064B 604505087B 1024B pad
17 604505088B 606041087B 1536000B sbl2b
18 606041088B 608138239B 2097152B sbl3b
19 608138240B 613381119B 5242880B abootb
20 613381120B 613905407B 524288B rpmb
21 613905408B 614429695B 524288B tzb
22 671088640B 1551892479B 880803840B ext2 system
23 1551892480B 2139095039B 587202560B ext4 cache
24 2147483648B 2148532223B 1048576B misc
25 2214592512B 2225078271B 10485760B recovery
26 2281701376B 2281709567B 8192B DDR
27 2281709568B 2281717759B 8192B ssd
28 2281717760B 2281718783B 1024B m9kefsc
29 2348810240B 2348843007B 32768B metadata
30 2415919104B 31272713727B 28856794624B ext4 userdata

5. Rename the system partition to disable it

(parted): name 22 unused1

6. Now you need to delete userdata partition:

(parted): rm 30

7. You need to create 2 primary partitions in place of userdata. First one will be the system partition. Second one will be the userdata partition. I recommend to have the system partition to start with the same byte userdata started and size divisible by 4096 bytes. Leave some space between the 2 divisible by 4096 bytes (block-size). Then have userdata partition start with a number divisible by 4096 bytes, size divisible by 512 bytes and ends where user data ended. I increased my system partition to around 2.93GiB (you can resize it whatever you want). I don't really need a lot of userdata. So my configuration would be:

(parted): mkpart primary 2415919104B 5570068479B
(parted): mkpart primary 5637144576B 31272713727B

8. Now you need to rename these 2 partitions:

(parted): name 30 system
(parted): name 31 userdata
(parted): p

9. Finally you need to create ext4 filesystem for system and userdata.

(parted): quit
~ # mke2fs -b 4096 -T ext4 /dev/block/mmcblk0p30
~ # mke2fs -b 4096 -T ext4 /dev/block/mmcblk0p31
~ # /parted /dev/block/mmcblk0 p

10. Have a final look at the partition table to see if everything is correct. Then Reboot into Recovery. This is a very important step. The mount configuration (/etc/fstab) doesn't update until you reboot.

~ # exit
adb reboot recovery

Done! You have a new system partition with a larger size ready for a ROM. The Size of the ROM will shrink after flashing a new ROM, Using TWRP, Wipe -> Advanced Wipe -> select system -> Resize File System -> Swipe.

Note: You might need to wipe cache/dalvik (might need wipe system too for mount to work), then unmount and remount system/cache/data for everything to work (for example, I had tablet's internal storage not showing on PC initially). But once everything works, it will always work:D

Final partition table looks like this:

Number Start End Size File system Name Flags
1 67.1MB 157MB 89.6MB fat16 radio
2 201MB 204MB 3146kB modemst1
3 204MB 208MB 3146kB modemst2
4 268MB 284MB 15.4MB ext4 persist
5 336MB 336MB 799kB m9kefs1
6 336MB 337MB 799kB m9kefs2
7 403MB 403MB 799kB m9kefs3
8 403MB 407MB 3146kB fsg
9 470MB 471MB 1536kB sbl1
10 471MB 473MB 1536kB sbl2
11 473MB 475MB 2097kB sbl3
12 475MB 480MB 5243kB aboot
13 480MB 481MB 524kB rpm
14 537MB 554MB 16.8MB boot
15 604MB 605MB 524kB tz
16 605MB 605MB 1024B pad
17 605MB 606MB 1536kB sbl2b
18 606MB 608MB 2097kB sbl3b
19 608MB 613MB 5243kB abootb
20 613MB 614MB 524kB rpmb
21 614MB 614MB 524kB tzb
22 671MB 1552MB 881MB ext2 unused1
23 1552MB 2139MB 587MB ext4 cache
24 2147MB 2149MB 1049kB misc
25 2215MB 2225MB 10.5MB recovery
26 2282MB 2282MB 8192B DDR
27 2282MB 2282MB 8192B ssd
28 2282MB 2282MB 1024B m9kefsc
29 2349MB 2349MB 32.8kB metadata
30 2416MB 5570MB 3154MB ext2 system
31 5637MB 31.3GB 25.6GB ext4 userdata

To increase cache size:

You have 880MB unused storage from the old system partition. You can keep it the way it is as you have the old system partition here which can be re-enabled quickly in the future. OR You can give this unused partition to the cache partition without messing around a lot. I recommend keeping a small unused partition in place of the old system partition to avoid messing with the order of recovery partition.

adb push parted /
adb shell
~ # chmod +x parted
~ # /parted /dev/block/mmcblk0
(parted): unit b
(parted): p
(parted): rm 22
(parted): rm 23
(parted): mkpart primary 671088640B 671096831B
(parted): mkpart primary 671096832B 2139095039B
(parted): name 22 unused1
(parted): name 23 cache
(parted): p
(parted): quit
~ # mke2fs -b 4096 -T ext4 /dev/block/mmcblk0p23
~ # quit