Here’s my translation
Alan
Þormóðr sá, er skotit hafði sauðnum til sauða Markúss, færði Lofti höfuð sitt um vetrinn eftir víg Markúss, en Loftr mælti, at hann skyldi sjálfr ráða fyrir höfði sínu.
That Þormóðr, who had driven the-sheep towards [the] sheep of Markús, surrendered (lit: conveyed his-own head) to Loptr during the winter after [the] slaying of Markús, but (and) Loptr spoke, that he himself should be-master-of his-own head (whatever that means?, <ráða fyrir e-u>, Z16).
Um þat var kveðin vísa:
About that was a verse recited:
[Version A]
Hvatvetna grét,
Wept for anything-whatever,
hefk þat fregit,
I have heard that,
býsn þótti þat,
That seemed a wonder,
Baldr ór helju.
Baldr out of the-abode-of-the-dead (Hel)
Þó hefr hæra,
Still has louder (lit: higher)
þás höfuð færði,
when [he] brought [his] head (ie surrendered)
Þórmóðr þotit.
Þórmóðr let-out-a-loud-sound (<þjóta>)
Þat es ólogit.
That is not-lied (ie true, <úljúga>)
[Version B]
[Note: the text I am using doesn't appear to have a version B]
[Version C]
Allir hlutir grétu Baldur úr helju.
Baldr weeps for all things out-of the-abode-of-the-dead, Hel)
Eg hefi frétt það.
I have heard that.
Það þótti undur.
That seemed a wonder.
Þó hefir Þormóður grátið hærra, þegar hann færði höfuð sitt.
Still Þormóðr had wept (even) louder (lit: higher), as-soon-as he surrendered.
Það er engin lygi.
That is no lie.
Of várit næsta eftir víg Markúss var áttr sáttarfundr of þessi málaefni.
During the next spring after [the] slaying of Markús, a peace-meeting was held (<eiga>, Z5) about this case’s-circumstances-and-nature.
Sá fundr var á Barðaströnd á þeim bæ, er at Haukabergi heitir.
That meeting was at Barðaströnd (Strand of various possibilities: warship-prows, helmet-brims, axes, etc) at that farm, which is-called at Haukaberg (Rock of Hawks)
Fyrir þeim fundi réð Hrafn Sveinbjarnarson ok Jón prestr Brandsson ok Krákr Þórarinsson, Steinólfr prestr Ljótsson.
Hrafn Sveinbjörn’s-son had command over <ráða fyrir e-u>, Z16) that meeting and Priest Jón Brandr’s-son and Krákr Þórarinn’s-son, Priest Steinólfr Ljótr’s-son.
Jón Brandsson var vinr mikill Lofts Markússonar, ok því bað hann Hrafn til at handsala fyrir Inga ok Guðlaug þingmenn sína eða fá menn til handsala.
Jón Brandr’son was a great friend of Loptr Markús’s-son, and therefore he asked Hrafn on-behalf-of Ingi and Guðlaugr to make-over-by-shaking-of-hands his Þing-men (liegemen) or to deliver-up people (men) as surety.
Gellir hét maðr Steinsson ok Jóreiðar Þórólfsdóttur.
[There] was a person (man) called Gellir son of Steinn and Jóreiðr Þórólfr’s-daughter.
Gellir átti Vigdísi Sturludóttur, en Jón Brandsson átti Steinunni Sturludóttur, en þó var sínum megin hvárr þeira at þessu máli, því at Gellir hafði tekizt á hendr Inga ok varðveitt hann á laun á bæ sínum.
Gellir had [in marriage] Vigdís Sturla’s-daughter, but (and) Jón Brandr’s-son had [in marriage] Steinunn Sturla’s-daughter (obviously the same Sturla from what follows), but nevertheless each (of the two) of them was on his-own side (ie on different sides) in this case, because Gellir had taken on his hands Ingi and kept him in secret at his farm.
Gellir var hávaðamaðr mikill ok heitrammr.
Gellir was a great self-assertive-person (man) and boasting.
En þá er Gellir vissi fund þenna, safnaði hann liði ok fór með fjölmenni til þessa fundar ok hafði með sér í för Árna, er óhelgat hafði Markús.
But (And) when Gellir knew of this meeting, he gathered troops and journeyed with a multitude-of-folk to this meeting and had with him in journey (ie had as a travelling companion) Árni, who had proclaimed Markús outlawed.
Þeir fóru með mikilli gemsan.
They journeyed with great gibing.
Ok er þeir váru á för komnir, þá sagði Gellir sik fleirum mönnum andvígan en einum.
And when they were (had) come on [their] journey, then Gellir said himself [to be] a match for more-people (men) than one.
Um þat var kveðin sjá vísa:
About that was recited this verse:
[Version A]
Verða nadda Nirðir,
nú emk út kominn, lúta.
"Víst munk fimm it fæsta
fella einn," kvað Gellir.
[Version B]
Nadda Nirðir verða lúta.
Northern Gods (pl of Njörðr) of studs (?) must bow-down.
Nú emk út kominn.
I am now come out
Víst munk einn fella fimm it fæsta," kvað Gellir:
Certainly I alone will fell (slay) five at least,” declared Gellir.
[Version C]
Bardagamennirnir verða að lúta í lægra haldi.
The-battle-people (warriors) had to bow-down in lower esteem.
Nú er eg kominn út.
Now I am come out.
“Vissulega mun eg einn fella ftmm menn hið fæsta," sagði Gellir.
“Certainly I alone will fell (slay) five persons (men) at least (fá, Z1),” said Gellir
Ok er þeir kómu til fundarins, þá var Lofti mjök óþokkat um þeira gems.
And when they came to the-meeting, then the-displeasure of Loptr was much (ie great) concerning their gibes (acc neut plural).
Því skaut hann spjóti í flokk Gellis.
Therefore he shot a spear into [the] band of Gellir.
Af því spjóti fekk sá maðr sár, er Hólmsteinn hét.
From that spear, that person (man), who was-called Hólmsteinn, received a wound.
Hann fell við skotit ok varð lítt sárr.
He fell on-account-of the shot and became (ie) was a little (ie slightly) wounded.
Ok síðan hljóp förunautr Lofts, sá er Óttarr hét, ok hjó í flokk Gellis, en maðr vildi stöðva höggit, sá er Örnólfr hét.
Ander after-that a travelling-companion of Loptr, that-one who was-called Óttarr, ran and hewed into [the] band of Gellir, but (and) a person (man), that-one who was-called Örnólfr, wanted to stop the-blow.
Hann var húskarl Steinólfs prests.
He was a manservant of Priest Steinólfr.