[Milestone XT720 General] Mioze7Ae:
I think it should be safe to use the fastboot recovery on XT720. I extracted the recovery.img from

RSTCU_U2_00.13.0_USASHLSTAB125P2XAPCNCU032.0R_HWp3_1FF.sbf

RSTCU_U2_10.16.0_SIGNED_USASHLSTAB125P2XAPCNCU035.0R_HWp3_1FF.sbf

I then extracted the recovery kernel command line to get the partitions structure (it was identical in these two sbfs):

console=ttyS2,115200n8 rw mem=244M@0x80C00000 init=/init ip=off motobldlabel=none mtdparts=omap2-nand.0:128k(mbmloader),640k(mbm),640k(mbmbackup),384k(bploader),384k(cdt),1536k(pds),384k(lbl),384k(lbl_backup),384k(cid),1536k(sp),384k(devtree),640k(logo),384k(misc),3584k(boot),3840k(bpsw),4608k(recovery),8960k(cdrom),384k(unused0),179840k(system),384k(unused1),106m(cache),203392k(userdata),384k(unused2),2m(kpanic),512k(rsv)

Here's a comparison with XT720 (2.1 and 2.2 and modsbf).

Motoroi XT720 2.1 Motoroi XT720 2.2
Milestone XT720 2.1 modXT720.sbf XT711 2.1
---------------------- ---------------------- ----------------------
mtdparts=omap2-nand.0: mtdparts=omap2-nand.0: mtdparts=omap2-nand.0:
128k(mbmloader), ... ...
640k(mbm), ... ...
640k(mbmbackup), ... ...
384k(bploader), ... ...
384k(cdt), ... ...
* 1536k(pds), ... ...
384k(lbl), ... ...
384k(lbl_backup), ... ...
* 384k(cid), ... ...
1536k(sp), ... ...
384k(devtree), ... ...
* 640k(logo), ... !!! ..., but not atags
* 384k(misc), ... ...
* 3584k(boot), ... ...
3840k(bpsw), ... ...
* 4608k(recovery), ... ...
* 8960k(cdrom), ... ...
384k(unused0), ... ...
* 204416k(system), * 173696k(system), * 179840k(system),
384k(unused1), 384k(unused1), 384k(unused1),
* 106m(cache), * 50m(cache), * 106m(cache),
* 177280k(userdata), * 265344k(userdata), * 203392k(userdata),
* 1536k(cust), ... !!! (missing)
384k(unused2), ... ...
* 2m(kpanic), ... ...
512k(rsv) ... ...

"..." means identical to the first column. The "*" means the partition is defined in atags structure passed from the bootloader to the kernel (they come from the CDT partition). Any partition loaded by atags is not touched by the version of part-STR.ko in the fastboot recovery. The part-STR.ko in OpenRecoveryXT720 is identical to the one in OpenRecovery and never worked (segfault on insmod).

Observations:

/system, /cache, /data partitions are different. This is OK because /system, /cache, and /data come from atags. part-STR.ko doesn't do anything with these.

/cust is missing on XT711 -- also not a problem because /cust is loaded from atags on XT720 and part-STR.ko doesn't do anything with it.

/logo does not get set by atags on XT711 and part-STR.ko doesn't do anything with logo, so nandroid of logo probably doesn't work on XT711 without fixing part-STR.ko

The total size of XT720 system+cache+unused1+userdata+cust == XT711 system+cache+unused1+userdata:

204416+384+(106*1024)+177280+1536 = 492160

173696+384+(50*1024)+265344+1536 = 492160

179840+384+(106*1024)+203392 = 492160

Everything before system and after unused2 has the same size

Conclusion: everything should work fine in fastboot-openrecovery except for nandroid of logo and cust won't work (and I think that can be fixed if necessary).

FYI: The source code for the part-STR.ko used in the fastboot openrecovery is here:

https://github.com/CyanogenModXT720/xt720_modules_eclair/blob/master/mtdhack/mtd-hack.c

Prebuilt modules here: https://github.com/CyanogenModXT720/xt720_modules_eclair/tree/master/prebuilt (mtd-hack.ko is part-STR.ko)