Non Volatile Storage

Same as PS3's NVS, used for storing tokens and flags. You can access it by using the function icc_nvs_read (or by ftp'ing the respective regions with root flags server).
Seems that a total of 7 regions(blocks) exist in 2 banks, main bank and backup bank
The kernel accesses only the 5th and the 2nd region, however it's possible to read the other 5 (also the entirety of it by reading /dev/sflash0s0x34 with BUF_SIZE 0x200 from ftp ).
Most, if not all, of the NVS regions can be accessed also in sflash, starting with offset 0x1C4000.

Mapping of the area (NVS service)

Bank #	Block #	Start Offset in /dev/sflash0s0x34	Start Offset in Sflash	Size	Notes
0	0	0	0x1C4000	0x3000	does not match, probably one (sflash or nvs, likely sflash) updates data
0	1	0x3000	0x1C7000	0x1000	match
0	2	0x4000	0x1C8000	0x800	match
0	3	0x4800	0x1C8800	0x800	match
0	4	0x5000	0x1C9000	0x3000	match
1	0	0x8000	0x1CC000	0x3000	match
1	1	0xB000	0x1CF000	0x1000	match

Mapping of the detailed area (NVS service)

Bank #	Block #	Start Offset	Start Offset in Sflash	Size	Notes
0	0	0	0x1C4000	0x8
0	0	0x20	0x1C4020	0x6
0	0	0x50	0x1C4050	0x1
0	0	0x60	0x1C4060	0x5
0	0	0x76	0x1C4076	0x1
0	0	0x7A	0x1C407A	0x6
0	0	0x80	0x1C4080	0x1
0	0	0x96	0x1C4096	0x3
0	0	0x9A	0x1C409A	0x2
0	0	0xAC	0x1C40AC	0x4
0	0	0x7FE	0x1C47FE	0x2
0	0	0x801	0x1C4801	0x1
0	0	0x810	0x1C4810	0x12
0	0	0x84C	0x1C484C	0x2
0	0	0x854	0x1C4854	0x2
0	0	0x870	0x1C4870	0xC
0	0	0x8A0	0x1C48A0	0x1C
0	0	0xFFE	0x1C4FFE	0x2
0	0	0x1000	0x1C5000	0x64
0	0	0x1220	0x1C5220	0x18
0	0	0x1240	0x1C5240	0x18
0	0	0x1260	0x1C5260	0x18
0	0	0x1280	0x1C5280	0x18
0	0	0x12A0	0x1C52A0	0x18
0	0	0x12C0	0x1C52C0	0x18
0	0	0x12E0	0x1C52E0	0x18
0	0	0x1300	0x1C5300	0x18
0	0	0x1320	0x1C5320	0x18
0	0	0x1340	0x1C5340	0x18
0	0	0x1360	0x1C5360	0x18
0	0	0x1380	0x1C5380	0x18
0	0	0x13A0	0x1C53A0	0x18
0	0	0x13C0	0x1C53C0	0x18
0	0	0x13E0	0x1C53E0	0x18
0	0	0x1400	0x1C5400	0x18
0	0	0x1420	0x1C5420	0x18
0	0	0x1440	0x1C5440	0x18
0	0	0x1460	0x1C5460	0x18
0	0	0x1480	0x1C5480	0x18
0	0	0x14A0	0x1C54A0	0x18
0	0	0x14C0	0x1C54C0	0x18
0	0	0x14E0	0x1C54E0	0x18
0	0	0x1500	0x1C5500	0x18
0	0	0x1520	0x1C5520	0x18
0	0	0x1540	0x1C5540	0x18
0	0	0x1560	0x1C5560	0x18
0	0	0x1580	0x1C5580	0x18
0	0	0x15A0	0x1C55A0	0x18
0	0	0x15C0	0x1C55C0	0x18
0	0	0x2000	0x1C6000	0x8
0	1	0	0x1C7000	0x50
0	2	0	0x1C8000	0x4C	Serial Number + model Type (CUH-XXXXX)
0	2	0x60	0x1C8060	0x58
0	2	0xC0	0x1C80C0	0xD
0	2	0x100	0x1C8100	0x20
0	2	0x7D0	0x1C87D0	0x10
0	2	0x7F0	0x1C87F0	0x1
0	4	0	0x1C9000	0x1
0	4	5	0x1C9005	0x1	Slow HDD Mode (0xFE ON) (0xFF OFF)
0	4	0x20	0x1C9020	0x1	init_safe_mode flag
0	4	0x80	0x1C9070	varies (0x68-0x6C)	acf token <- checked by sceSblDevActVerifyCheckExpire
0	4	0x100	0x1C9100	0x100
0	4	0x200	0x1C9200	varies (0x40-0x60)	scrambled/obfuscated eap hdd key <- checked by g_crypt_deferred_init
0	4	0x31F	0x1C931F	1	UART boot param? (setting this to 1 enables UART output on boot)
0	4	0x900	0x1C9900	0x100	acf signature
0	4	0xC00	0x1C9C00	0x170
0	4	0x1000	0x1CA000	0x300
0	4	0x1300	0x1CA300	0x300
0	4	0x1600	0x1CA600	0x1	IDU Mode? (set to 01 to enable?)
0	4	0x1601	0x1CA601	0x1F	checked by regMgrNvsSpInit
0	4	0x2C00	0x1CBC00	0x20
0	4	0x2C40	0x1CBC40	0x20
1	0	0x31F	0x1CC31F	1	unknown