Uspex Z15e SD installer (2.0)

Z15e edition of the Uspex custom Z15-family firmware. Verified identical
hardware platform: same BOOT.bin, kernel and device tree as the Z15 build.
The patched cgminer, the profile machinery and the web UI are adapted for
the Z15e chip grade.

2.0 highlights:
- Z11 fan model. ONE fan regulator drives the fans: Auto holds the hottest
  chip at 78 C; TT mode holds the user target (60-95 C); Manual is an honest
  percent through the measured Z15e duty->rpm map. Anti-hunting: a step is
  applied only after two consecutive ticks agree, deadband +/-2 C, climb
  +4% / descend -2%, straight to 100% at 84 C. Restarts are bumpless and
  fan changes never restart the miner (register poke delivery).
- The new Fans web page holds all fan control (Auto / TT / Manual) with
  live rpm boxes.
- Target scan is FREQUENCY-ONLY on Z15e: the power rail is fixed by the
  on-board PIC (~780 mV) and is NEVER written. Per-board frequency walks
  the PLL grid (from 750 MHz, cap 850 MHz) in one-hour windows; a point is
  locked only when a REPEAT window confirms it; an unconfirmed repeat climbs
  HIGHER. Cloud scan target is fixed at 200 kSol total (70 per board).
- Fast pages: one cgminer-API fetch per render with a 2 s cross-CGI cache
  and pure-shell field extraction (no fork chains).
- Password change is its own menu item: one step changes BOTH the web
  (digest) password and the root system password.
- Board voltage UI removed everywhere (voltage is not controllable on Z15e).

Profile ladder (cards in this order):
  Low         750 MHz
  Stock       800 MHz
  Target scan  (appears only after a correctly finished scan)
  Performance 825 MHz
  Overclock   850 MHz - REQUIRES a strong PSU and improved cooling.

Hard safety caps: frequency limiter 870 MHz. The board voltage stays the
stock ~780 mV set by the on-board PIC.

Fan behavior: fan "Fan Err!" transient low-RPM threshold raised (no false
fan-error reset at spin-up). Immersion (liquid) mode: fan thermostat off,
fans pinned at 100% as an anti-mistake safety net; the 95 C ladder still
stops mining. Factory reset and firmware flash stop any running scan and
clear scan state.

WARNING: this installer erases the user config partition (mtd2) - pools,
web password, network settings and profiles are reset to factory values.
After flashing the miner boots in the Stock profile. First boot credentials:
SSH root/admin, web root/root.

LED behavior: GREEN blinks while preparing/verifying, then ALTERNATING
red/green while the firmware is written, SOLID GREEN = completion.
SOLID RED indicates a real failure; the previous firmware stays intact.
The install log is written to Z15e-INSTALL.log on the card.

1. Format a 4-16 GB microSD card as FAT32/MBR.
2. Extract every file and the bin folder to the card root.
3. Power off, insert the card and power on.
4. Watch the LEDs as described above (normally 5-10 minutes).
5. Power off, remove the card and power on normally.

This package keeps the existing NAND bootloader, environment and device tree.
It writes the primary/backup firmware ramdisks and their matching kernel slot only.
